Table of Contents
- HEROES OF MIGHT AND MAGIC 3: COMPLETE EDITION - IMPOSSIBLE CAMPAIGN GUIDE
- ADVENTURE MAP STRATEGIES
- BATTLE STRATEGIES
- CAMPAIGN STRATEGIES
While there are many guides for HOMM3, few guides are specific for the campaign itself. Most guides for HOMM3 apply to multiplayer or scenarios. The guides that do exist for the campaign simply says go here, take this town, then go here without explaining how to do that or specifying the difficulty their strategies work on. Other guides are just a list of random tips like “Send an army of Wraiths split into 1 size stacks to drain the enemy mana!”. These sorts of gimmicky plays are cheeky but will almost never win you the campaign alone. Other guides are nothing more than statistics of heroes and creatures. None of these help the player in practical terms what to do from Day 1 to Day 28, the most critical part of the game.
The goal of this guide is to help the average player who understands the basic rules and concepts but struggles to beat campaign maps. If you've played more than 2 hours of the game this guide is for you.
Gameplay in Heroes of Might and Magic 3 can be separated into two components: Adventure Map Strategies, and Battle Strategies. That is how this guide will be ordered. A third component unique to the campaign, Campaign Strategies, will also be featured.
Your success on any given campaign mission will largely be determined in your opening 2-3 weeks. While glorious battles between hundreds of Gold Dragons and Archdevils make for good screenshots, this is not likely to happen over the course of the game. Some of your most important battles will be with a handful of lower tier creatures clearing out a neutral camp that enables you to access a clutch Gold Mine or stack of Crystal.
The key in most maps is aggression. If you take nothing else from this guide, this is the most important part of being successful. You need to be claiming mines, building up your town, and yes, even sieging enemy castles in those first 2 weeks if the opportunity presents itself. It's rare for any map in the campaign to go beyond 2 months of meaningful play, and within a month you should know if the game is winnable or not. Your opponent will start with a 2-3 town advantage and often a resource advantage as well. You will fall behind if you just sit back with your first town and try to build up from there. The only time you can let up the pressure is when you have a town and resource advantage, but at that time the map is basically won. I assume you are playing on Impossible difficulty, but the concepts provided will work for all difficulties.
Your first order of business on Day 1 should be acquiring at least 2 extra heroes. Locate the nearest Gold Pile or Treasure Chest, and buy that second hero. One of the biggest mistakes of new players is not getting enough heroes. You will likely need 2-3 secondary heroes for each primary hero you control. Your primary hero needs to be fighting, period. They cannot be spending time picking up resources, flagging mines, or even going to External Creature Dwellings.
Even gathering resources that are right next to your hero takes movement points. Let these secondary heroes flag mines, go to creature camps, pick up resources, and shuttle creatures to your hero. You can move an entire army half way across the map in a single turn by training together a series of secondary heroes. The Mystical Garden, Windmill, and Waterwheel are excellent sources of income early on that should be abused by these heroes. The starting units they come with will also be invaluable as fodder units for your main hero during the first 1-2 days .
2500 gold for a hero may seem like a waste, especially if you're buying a hero with only one tier 1 unit after already buying 2 heroes that week, but they have no maintenance fee, and can easily pay for themselves by flagging a single gold mine, or even visiting a water wheel a few times, never mind the benefit of just exploring the map. If you are ever unsure if it's worth getting another hero, the answer is usually yes. The only rare exception may be saving money to buy that key Creature Dwelling on day 7.
Your first week should be spent claiming as much territory as possible and clearing out as many feasible neutral camps as you can, all while suffering minimal losses. Ideally in each fight you will only lose single digit numbers of tier 1 troops. "But how is my army of 30 goblin and 10 orcs supposed to defeat X?" See the Battle Section. These first fights will get considerably easier as the campaign continues and your starting hero becomes more powerful.
All Treasure Chests should be claimed for gold. Always. You are guaranteed to max out your main hero's level in each campaign map, and the experience would likely otherwise be wasted on a secondary hero. You need that gold to pay for dwellings, creatures, and secondary heroes.
Maximizing your hero's movement will also enable your blitzkrieg across the map. Total movement points is based on the speed of the lowest initiative creature in your army at the start of any given day. Those Dwarves you brought with you aren't just useless in battle, they may be slowing down your entire army. One possible work around is to use a secondary hero to ‘hold' these slow creatures and swap them back and forth. If your hero ends their turn in a town, dump all but the fastest creature into the Garrison before you hit end turn. Just make sure your main hero has only fast creatures in his army before you end your turn. Stables, Rally Flags, and Fountains of Youth can also increase your movement speed. Most artifacts guarded by higher level creatures are rarely worth it, unless it's for Gloves of the Equestrian or Boots of Speed.
Eventually you will come across either an enemy hero or their town. It's more important to take a town over killing an enemy hero. Capturing enemy towns is how you win the game, regardless of what the scenario objective is. The swing it generates in your favor is huge. Obviously it gives you gold, but it also denies the opposition gold, creatures, and potentially even resources. Secondly, it will be much easier to defend your own hero from inside castle if the enemy hero decides to attack you.
Do not build many structures in these towns. At best they will be money sinks and at worst they will get retaken and abused by the AI. Instead, buy a hero from the Tavern in that town to flag all the surrounding mines the AI has invariably taken and left unguarded. It's probably worth getting City Halls in these structures, and if it'll pay off, Resource Silos. At most you will be able to support 2 towns of your faction in the first 2 months of the game. All other towns should be considered Gold Mines and Town Portal targets. Defend them if you can, and buy up all the creatures if it's going to get retaken by the opponent.
Below is a complete first level using these strategies for both Might and Magic Heroes:
If you've been dutifully clearing creature camps, collecting resources, and buying heroes, the next big decision is what to spend this money on. Your first few purchases are going to be clutch.
In general get a Town Hall built first if you don't start with one, then go after your 'key' creature structures (see below). Then you should transition over to getting the City Hall and eventually a Capitol. In most cases defer upgrading creature dwellings. Note this doesn't apply for very key upgrades (Archers, Gremlins, Vampires, Elves), but in general. While most expensive, the tier 7 upgrade is often worth upgrading before most anything else if you can get it. The priority from there should be upgrades that provide increased move speed.
Avoid building your Mage Guild (except level 1), support structures (Halls of Valhalla, Mystic Pool, etc.) until you are closing out the game. Build the Resource Silos when you are flush with cash.
The 'build' order of your town in wholly dependent on what faction you are playing. The biggest mistake new players make is haphazardly building or upgrading random buildings without aiming for specific creatures. Some creatures are terrible and only worth getting if you have money to burn. Some upgrades only offer a marginal benefit or are too expensive to be worth it. Most towns have very specific creatures that you should be gunning for as they are extremely powerful early. Let's look at opening creature strategies for each faction.
All of Castle's units are strong and worth getting, but prioritize Marksmen as the double-shot is obviously amazing. Their weakest unit is probably the Monk and it's not even that bad. Their Blacksmith provides Ballistas and is worth getting for the appropriately statted hero. Upgrading to Crusaders is recommended before buying any Swordsman, and Gryphons also get a significant power boost from being upgraded too. You can do plenty with just the first 4 creature swelling. Archangels are probably the best tier 7 unit in the game
This is my pick as the weakest town. While its creature quality is high they are also very expensive in raw gold and building cost. The Beholder dwelling annoyingly costs 1 of every resource, no easy task on Impossible for such mediocre creature. Getting a foothold with this Faction is a pain. Early you'll rely on Beholders & Medusae for their mediocre ranged damage and protecting them with Troglodytes. The only creature in the game that may benefit from the generally terrible Ammo Cart is the Medusa, and the Dungeon Blacksmith doesn't even offer it.
What you really need to be aiming for are Minotaurs, they are tough as nails and hit extremely hard for their cost. Minotaur Kings have a speed of 8 and thus can be used to kill ranged units. If you have the gems this is worth doing. Harpies should be upgraded as they act as a pseudo-ranged unit with their no retaliation. Manticores are below average and their structure is expensive. Black Dragons are amazing but they are extremely expensive both in raw resources and in pre-requisites. You'll be relying on spells to win most of your early game after the first campaign map. Dungeon is a rare Faction during the campaign.
Commonly thought to be a weaker faction by new players, the Fortress has very powerful and importantly accessible mid tier units. All Fortress units have high defense values, even their archers (not necessarily an efficient distribution of stats). If you can, rush Wyverns immediately as the pre-requisites are small, the only impediment being wood. They can be had in a few days and will make clearing ranged camps much easier. Upgrading them really only provides a useful speed buff and isn't a priority. Gorgons are the best tier 5 unit in game due mostly to their stat distribution. They are incredibly tough to kill. Their secondary skill is likewise great as it can destroy tier 7 units with even one Mighty Gorgon. Serpent Flies are also worth getting as their high speed allows them to pick off creatures easily and will almost guarantees you first play in combat. Upgraded they can clear the map in one turn, making archers very easy to kill. Basilisks are merely average & Lizardman are sadly some of the weakest archers in the game. Chaos Hydras while amazing when engaged are just too slow. The biggest weakness of this faction is the slow speed of all their units and lack of any decent ranged units. Therefore, Air Magic & Tactics should be skilled as Mass Haste is very effective for this town.
Criticized as the worst Town and for good reasons, their one bright spot is being able to put out Efreets early. This should be prioritized as they are extremely fast, reasonably tough, and hit very hard. Being a fire themed town they are more likely to get Armageddon when upgrading their Mage Guild, making the Armageddon+Efreet combination actually feasible. Magogs are weak ranged units that is only partially made up by their splash damage which also does friendly fire damage. Cerebri are probably their best lower tier unit due to the multi headed attack, speed, no retaliation, and overall damage. Other units including Devils are just mediocre, and are over priced. Castle Gates seem awesome but they are very expensive and require you to have taken a second Inferno town, a point where you are likely winning already. While weak, you will rarely play Inferno through the 3 Campaigns.
There are only 2 things to know to be successful with Necropolis: Vampire Lords and Necromancy. Vampire Lords can single handedly clear most neutral stacks without losing any men. Your goal is to get these creatures out by Day 1 of week 2, and then never lose a single one. They can kill ranged units and hordes of low tier units without losing a single unit. Their only weakness is against other undead or elemental/mechanical units (no life drain) or tougher tier 6 or 7 units that have too much defense to translate their damage into resurrecting units.
It's a good thing Vampires are so great. because Skeletons, Zombies, and Wights are below average. Fortunately Liches and Dread Knights are excellent, but Bone/Ghost Dragons are one of the worst tier 7 units. Necropolis is still a very strong faction mostly on the back of Vampire Lords and Necromancy. Unlike most factions, getting their specialty building (Necromancy Amplifier) is important to snag early. After your first campaign level, a Necromancy Hero with Death Ripple, Logistics, and Expert Necromancy will steamroll the map with very little resistance. They have the easiest Campaigns even on Impossible.
If you are confused how the Ghost Dragon ability works, it halves the hit points of each monster in a stack, it doesn't reduce the stack size by half. What this means is a 10 stack of Behemoths with 150 hps, is now a 10 stack of Behemoths with 75 hps. In effect, all attacks against that creature now do double damage (unfortunately the damage is applied after the effect by the Ghost Dragons).
Get Grand Elves and start killing things. Centaurs are the best tier 1 unit in the game both for their above average damage and hit points but also a very respectably move speed. Elves and Centaurs will form the bulk of your week 1 army for the Rampart. Pegasi are very fast and in good numbers can one-shot stacks and can avoid a retaliation that will hurt their flimsy hit point totals. They are one of the few sub-tier 7 units that can clear the entire map in a turn, and you should use them for clearing stacks of ranged units. Ignore Dwarves and Treants, they are just too slow especially without upgrades. Unicorns are just average tier 6 units. Dragons are excellent but their pre-reqs make it hard for them to make an impact early game when it matters.
The infamous Treasury Building, while eventually worth getting, will likely only make a won game that much more closed up. It generates 10% of whatever gold you have on Day 7. If you have even 10,000 gold, that's only 1,000 gold a week. Early on 10,000 gold is not easy to horde, and doesn't justify the obscene 5,000 gold investment cost of the Treasury. Don't prioritize it. Spend the money on a Castle or Resource Silo.
One of the few factions that can get their tier 7 unit in the first week: The Behemoth. This should be your priority and can be done even with no starting resources. As far as their other creatures go: Rocs are easy to get and you need these in the first week in the event you don't get your Behemoth. Goblins have slightly above average damage and are worth getting in a power stack. The upgrade to hobgoblin provides a very respectable movement bonus. Orcs are a weak tier 2 unit but as they are ranged worth getting. Wolf Riders are incredibly flimsy and only powerful when upgraded which is usually hard to get early. They are preferentially targeted by the AI to make matters worse. You can safely ignore Ogres and Cyclopses until later. The cost of the Cyclops structure is obscene, you're much better off going for Behemoths. The wood cost on an Ogre Fort is prohibitive and Ogres are just too slow.
If you are unclear how the special ability of Behemoths work, its attack ignores 60/80% of the targets defense. So if a Black Dragon has a defense total of 25, for the purposes of calculating damage from the Behemoths' attack it will only have a defense of 5. This is simply bonkers. Your Behemoths should be focusing the highest tier unit on the field every time to not waste this ability. Note this is not a debuff, despite what the tooltip says. It only applies to the Behemoths' attack. You should be wary of fighting of Behemoths as they will do significant damage to your higher tier units even if your hero has a superior Attack/Defense. Eliminate them with spells and ranged units or tie them down with Blind or Slow before they can get a hit in.
Master Gremlins are nice for their ranged damage and should be upgraded quickly. They are extremely frail even relative to most tier 1 creatures. The AI prioritizes them in combat and you can guarantee they will be targeted and ripped apart by spells, archers, and any melee fighters that get in range. They are still worth getting but need to be walled off with Golems or other slow melee units. Golems and Naga tend to be too slow but Genies and Gargoyles are worth getting. Unfortunately plain Giants are almost useless, but Titans are great (and expensive!).
Throughout the above review I have denigrated various poorly statted creatures. That is not to say they have no value whatsoever. A Rampart protected by a big stack of Treants is a huge pain for the AI. I'd rather have 5 Manticores than 0 Manticores. Using Dwarves for cannon fodder against some aggressive flying neutral monsters is a good early use of them. My suggestions above are just an order of priorities based on the scarcity of resources in the early game. When wealth abounds, buy whatever you want.
Sneered at by elitists, saving and saving frequently will not only keep your game viable but will let you learn the game at your own pace. I keep eight save games during the campaign, one for each day of the week, and one as a throwaway ‘test' to see if a particularly battle was winnable or not. Autosaving is not reliable enough as it's very easy for your over extended hero to be jumped out of the blackness by an overwhelming force that you have no hope of winning. If you autosave you'll just be reloading your hero with 0 movement points and no chance to pull him back. Autosave is primarily useful for buying units in undefended towns that are being sniped by opportunistic enemy trash heroes.
There is no shame in this. Once you are more familiar with the game, judicious use of spells like View Air and View Earth will prevent frequent reloads. Retry battles as needed, and experiment, experiment, experiment. Once you get good, then go try an Iron Man run.
Unlike scenarios, you are given a hero with their own starting skills and specialties. You have (almost) no choice in the matter. You will succeed or fail in large part based on how you build your hero. The disadvantages you experience at the start of each map are offset by the fact you will start with a high level hero, and if he has not been leveled properly, you will have a very hard go of things even if you've followed my advice up to now.
As the name implies, Heroes are either Might focused or Magic focused. Might Heroes do not start with a spell book (and you absolutely should buy one for each hero) and have a predilection for the Attack and Defense stat over Wisdom and Spell Power as they level up, and will more often than not be offered Combat based secondary skills over magic ones. Magic Heroes are exactly the opposite.
These are your Attack, Defense, Spell Power, and Wisdom rating. While the math behind the calculations can get complicated, simply put: Attack raises the damage your creatures do, Defense reduces the damage you take from other creatures (but not spells!), Spell Power increases damage/duration of spells, and Knowledge increases your mana. You have limited control over these as a random one is increased by 1 when you level, influenced by the kind of hero you have.
No other decision you make will have a greater effect in your campaign than the Secondary Skills you pick for your Campaign Hero as you level him. A campaign can go from literally impossible to a breeze with the correct skills chosen. Because heroes and their skill choices carry over, selecting the right skills is all the more important.
You are limited to 8 skills. Once you've picked a skill you are stuck with it for the rest of the campaign, not just the map. You must avoid at all costs getting stuck with a dud skill, of which there are many.
When you level up, you are offered a choice between 1 new skill or leveling up a skill you've previously chosen. But once your skills are all Expert Level, you will only be offered 2 Basic Skills, and will run the risk of choosing between 2 clunkers. So if a Basic Skill you want comes up, pick it even if you have to forgo a key Expert level skill, because you will always have the opportunity to level up an existing skill, but that Basic Skill might not come up again.
For example, you are offered Expert Air Magic or Basic Logistics. Expert Air Magic is a huge upgrade as it enables Mass Hate, but Basic Logistics is also very good (but not as good as Mass Haste). Regardless you should pick Logistics in most every case. You are guaranteed to be offered Expert Air Magic later on, but you may not get a chance to pick Basic Logistics again.
One work around to this are Witch Huts, Scholars, and Universities. These offer random Secondary Skills that may otherwise be difficult or even impossible for either a Might or Magic Hero to get. These are always worth checking (but save first! It doesn't give the option to refuse the skill!) to see if they offer a desirable skill. I have restarted an entire Campaign map that was effectively beaten after being offered 2 terrible skills and having Witch Huts offer equally terrible ones.
Below is the complete list of skills and their rating
As mentioned, the most important thing is speed, and the easiest way to get that is through Logistics. Your success in the game will largely be determined by your map play, not battle tactics. Everyone movement counts, and every hero needs this, both your main and secondary heroes.
Expert Earth Magic is by far and away the best school of magic in both battles and adventure map play. Expert Level Town Portal, Slow, Shield, Stone Skin, Implosion, Resurrection, Raise Dead, Meteor Shower, Death Ripple, and even View Earth and Anti-Magic are worth using. Even Might Heroes will enormously benefit from Mass Slow, Shield, and Stone Skin even if they don't have Wisdom.
So broken it's often nerfed in competitive play. It's rarely an option since all Necromancy heroes start with the skill and no other heroes can even get it. Nevertheless it's worth leveling over most other skills. Skeleton Warriors will only be resurrected over Skeletons if 3 criteria are met: You have no free slots in your army, you have no plain Skeletons, and you have at least 1 Skeleton Warrior. As powerful as this seems you resurrect fewer Skeleton Warriors than Skeleton if using this.
If you've had limited experience with the Ballista, it may seem terrible. And indeed, a level 1 hero without any points in the skill will find it terrible. But Ballista damage is based on both the Ballista skill and Attack Power of your hero. For Might Heroes the damage can rapidly increase as they level up. Once you reach 10+ Attack, your Ballista will single handedly wipe out neutral stacks and even tier 7 monsters. This skill is rather poor in scenarios because you always start at level 1. But on Campaigns when you can start a level at level 9+, Ballistas become much stronger. In some campaigns your Might Heroes just won't have the spells to help them in that critical first week. Artillery let's them bridge that gap.
The difference between having Expert Artillery, and no Artillery at all is a 3 fold difference in damage, so buying a Ballista without Artillery will give you much less damage (in addition to be being able to control its target). It's like having the attack power of a Titan at the beginning of the game.
Some caveats: Only get this skill on Might Heroes of the Castle, Dungeon, Conflux, and Stronghold as their Blacksmiths (or Ballista Yards) can actually buy Ballistas. It's not worth it on Magic Heroes, they can just use spells to clear neutrals early game. Keep in mind Ballistas are never available if you are defending a castle or if you are raiding a Creature Bank (Dwarven Treasury, Naga Banks, Cyclops Stockpile, etc.).
Gives a 30% increase in Damage for all melee creatures. This is equivalent to a 6 point increase in your Attack Damage. Compared to the overrated Luck, that only gives you a 12.5% chance to “double” damage and Offense beats it handedly (despite not applying for ranged units).
Gives a 15% decrease in Damage on all creatures. Note this works against ranged damage. Useful on all heroes, even Magic ones, by helping to keep your creatures alive while you nuke down enemy creatures.
As Spells are tied to the hero as you progress through the campaign, Wisdom is highly desirable. It doesn't quite reach the "ALWAYS" level mostly because the high tier spells are very expensive and Might Heroes can rarely these spells often enough before they're out of mana.
Mass Haste is the biggest, if not only, reason to pick Expert Air Magic. The effect is huge. It's especially effective on Castle, Stronghold, and Fortress Heroes when combined with Tactics. They usually get initiative first because of Dragon Flies, Lightning Rocs, and Archangels which means you can cast mass haste immediately, and then all your troops can reach the enemy immediately before any of their units even gets a chance to move. Even without Tactics, if you “Wait” with your units, let the enemy approach, and then cast Mass Haste, your entire army will likely get to attack twice, once when the wait has expired, and immediately during the second round of combat.
Lightning and Chain Lightning are excellent spells for destroying early camps, but at Expert it only gets a flat damage increase. You don't need Expert level for it to be useful. Dimension Door benefits from Expert Air Magic, but it's hard to get that spell in the first place.
Leadership seems good but maxed out it only gives a 12.5% chance of a second attack. Frequently the extra attack isn't necessary or even wasted (the classic example is hitting "Defend" and using the extra turn to .... Defend again). Second, Morale caps at +3, which can often be gained with artifacts or structures around the map.
Understanding why Logistics is fantastic and why Pathfinding is mediocre comes in understanding how each works (not how similar their pictures are!). Without getting too complicated, Logistics will always increase your move speed on any terrain, whereas Pathfinding will only increase it on hostile terrain. Generally this means Swamp, Snow and Desert. Not enough campaign maps feature this kind of terrain and those that do you are usually playing Fortress or Tower and won't have the terrain penalty.
A free half a gold mine seems good to start the game with, but your primary source of gold early are going to be treasure chests and piles, not 500 gold / day. And to get those chests you have to win battles, and Estates doesn't do that. Late game 500 gold/day is negligible.
Mass Prayer is excellent but is a 4th level spell. Mass Bless, Mass Weakness, and Mass Dispel/Cure can be helpful too. Mass Forgetfulness can be amazing against neutral ranged camps, but it's probably better just to Chain Lightning/Destroy Undead/Death Ripple them instead. Clone and Teleport are situational but at times helpful. Water Walk seems good but because you have to 'see' your destination (you can't stop in the middle of water) it's rarely helpful on the Campaign Map.
At Expert level it's a flat 15% increase in damage. It seems small but you're going to be relying on spell damage in the second and higher campaign levels to clear neutrals out. Not terrible but most of your damage is coming from spell power anyway. Obviously only for Magic Heroes, but not a bad choice and can help you clear neutral monster in the early stages of the game.
Controversially I've put this in the Optional category, but Diplomacy is utterly broken in Scenario play. Diplomacy at first glance seems almost useless. You often can't afford to pay for the stacks willing to join you and the second part, reduced Surrender cost, is literally unplayable as it will cause you to instantly lose the map in Campaign play. But Diplomacy does not just let you 'buy' creature stacks, it also reduces the threshold that they will join you for free. This calculation is determined by both diplomacy level and how powerful your hero and its army is. This means once a single stack joins you for free, other stacks are more and more likely to do so creating a rapidly increasing snowball of joining creatures. However in Campaign play I found it hit or miss when creatures would join me, and creatures that could join me I could usually destroy easily anyway. Certainly worth experimenting with.
Most of Fire's useful spells are just direct damage (Fireball, Inferno, Armageddon) that gain little by Expert casting, and its best spell (Blind) has a negligible benefit at Expert Level. It is saved by Expert Berserk, allows you to cast is in an area. Berserk is reasonably effective as a single cast though anyway, and requires Wisdom to use unlike other mass cast spells. Mass Curse does have some merit. The dream of Armageddon + Dragon/Efreets rarely materialize in game.
I find Tactics some what overrated. Obviously it's nice to get your slow moving troops half way across the Battlefield, and being able to establish a wall of meat shields in front of your archers is often handy against very fast neutral camps. But most of the time starting your units that close to the enemy isn't even enough for slow units like Treants and Zombies to even reach the back lines. The one place it ought to shine is for Might Heroes facing a stack of ranged units. But even here most of your tier 1 and 2 units simply can't close the distance in a single turn even with Tactics. Worse, the archers can just shoot them immediately because they have initiative and have no ranged penalty as they have they are starting so close. And on sieges Tactics has almost no use at all. As mentioned above, it can be very powerful when combined with Expert Haste as it guarantees your entire army will engage the enemy immediately, but outside of that it gets more praise than it deserves.
On its face Luck appears to be the flip side of Morale, but Morale is almost always better. Often doubling your damage just overkills a stack, whereas Morale let's you attack another stack entirely. And, just as with Morale, Luck maxes at +3 which can be obtained from items without wasting a skill slot. Also, while negative Morale can be very bad, there is no negative Luck that needs to be countered.
For most heroes Archery isn't useful except Might Heroes in the Castle, Rampart, Tower, and Dungeon. Additionally this does increase Ballista damage (and less significantly gives you control of archer towers during sieges). If you have heroes from the above factions or are using a Ballista this is a lot better. These factions use a lot of ranged damage and a 50% increase is nothing to sneeze at. Your biggest exposure to Archery in the Campaign will be with Gelu who starts with this and his Sharpshooters' damage is nuts.
Most of your castle sieges will not be won by smashing down the walls and marching your troops through the openings. It'll usually be your fliers and spells that eliminate the enemy. Ballistics' biggest benefit is destroying the archer towers but even though you get to 'control' the catapult it still frequently misses what you mean to attack. Given this is only moderately useful for one specific type of battle it's almost never worth getting. If you're trying to destroy castle walls use Expert Level Earthquake. The only other benefit it provides is you get to cast spells first, as the catapult always gets first attack.
Decent on Secondary Heroes, though not as horrible as you'd think on your main. As your main hero is usually at the vanguard, knowing what's ahead can be helpful, but probably not enough at compromising your ability to win battles.
Not as bad as it first appears. It can be situationally useful for Might Heroes oddly enough. It helps expand their mana pool by effectively doubling their Knowledge stat. This will typically be far more helpful that Mysticism in most cases for increasing spell casts, but you'll likely want a different skill regardless. Do not get this on Magic heroes, their mana pools are usually big enough, especially as the campaign progresses.
You are forced to get this with Gem who starts with this ability as a specialized skill and it's still terrible. In Heroes 5 it can resurrect creatures but it doesn't in Heroes 3. That means it's only good for tier 6 and above creatures who can take 100 damage without dying and benefit from the First Aid heals. You are unlikely to have these creatures early anyway and by the time you do, a 100 hit point heal is meaningless. With a mere 75 hit points the unit itself will literally fold like a cheap tent if targeted by the enemy. The only teeny tiny exception to First Aid may be Fortress Heroes, because they can get both Wyverns (Tier 6 creature) and First Aid Tents early on. Otherwise it's utterly worthless at all stages of the game.
Only useful on one map in the entire campaign where there are literally no Magic Guilds and no Wells/Springs. 4 mana per turn is too negligible to matter. Just use Wells or better yet, Town Portal to a town and rest at a mage guild.
In summary my 'dream' build for a Might vs Magic hero:
Might - Logistics Offense Armorer Wisdom Air Magic Earth Magic Artillery (Tactics/Archery/Necromancy)
Magic - Logistics Offense Armorer Wisdom Air Magic Earth Magic Sorcery (Water/Fire Magic, Tactics, Necromancy, Diplomacy)
It is no mistake these look so similar. The reality is in the later campaign levels Attack, Defense, Spell Power, and Knowledge will all be in the teens due to stat boosting buildings no matter what hero you use. The "Might" and "Magic" convention blurs significantly eventually being distinguished only by secondary skills. Even your Barbarians will be casting Implosion before the campaign is through.