For any mage, Arcane Warrior is a must. Having her wear heavy armor and having the crazy buffs that come along with Arcane warrior will make her, and any other mage, hard to hit and extremely resilient. Dont forget to also get all the other readily available buffs like rock armor, spell wisp and their are a few more that i cant remember.
Some armour combinations can really negate the fatigue increase, particularly armour sets which reduce the cost of talents. I usually set Wynne up as a Spirit Healer/Arcane Warrior and deck her out in the Ancient Elven Armour.
The only disadvantage with making a party member a Blood Mage is their tactics are quite difficult to set up. You have to have something along the lines of:
Health > 25% -> Deactivate Blood Magic
Health >= 90% -> Activate Blood Magic
Enemy -> Clustered -> Activate Blood Wound
Etc. The only thing is they will continually be activating BM outside of combat which will deactivate again.
Depends on play style. If you $ glitch the crap out of the game infinite high potions are at your disposal so go buff's/offensive.
It has been a while but I think she has the class that has all the buffs (summon undead, haste,etc..) at first doesn't she? If not pick that.
I find her to not be a prime choice playing the game normally because taking on that quest is long and can prove to be hard if you do it right off the bat - and if you wait and goof around she will be higher in levels and the stupid AI will auto assign her talents poorly. Playing the game normally means getting the ones you plan to use asap.
But yeah this game is full of tricks so do whatever you want.