Blackout Kick proc: 20% extra parry and more "reduction" from stagger. Guard: Like a super powered shield barrier every 30 seconds, OR if you glyph it then you can usually keep it up a lot more getting more self-healing from the buff. Stacking hit, exp., haste has the main benefit of the aforementioned Elusive Brew which will give you 30% dodge while the buff is up. The stagger mechanic redirects damage into a DoT debuff. That debuff can be cleared by an ability that consumes 1 chi and has no cooldown.
Monks are fine now. However in the foreseeable future they may end up hitting a theoretical soft cap where they can have close to 100% uptime on all buffs including elusive brew. Currently stacking haste and crit over mastery offers the most benefit. If/when this soft cap is reached in a future patch, you would stack mastery after a sufficient amount of haste and crit. This will make reforging that much more complicated, and it would also mean that monks scaling with gear is diminished after that point.
Also monks do not have an obvious AoE rotation. They have something of a trilemma when it comes to large packs: (Why is trilemma not in the GFAQs dictionary?)
1) Use Dizzying Haze as a filler. The advantage is that you can continue to melee while doing this building up stacks of elusive brew and have astronomical AoE threat. The disadvantage is that you will be chi starved and may not be able to keep up Shuffle. Also your DPS will be lower.
2) Use Spinning Crane Kick as a filler. The advantage is that you do high AoE DPS, maintain high threat, can keep shuffle up by weaving blackout kicks. The disadvantage is that you are not meleeing during spinning crane kick losing out on elusive brew stacks.
3) Use Breath of Fire as a filler. Here you get the maximum benefit of your defensive buffs, but your AoE threat and DPS are reduced.
Usually a mixture of the three is best. It is not wise to simply spam spinning crane kick, for example, on the adds against Wind Lord. Monks that do that are harder to heal. But of course after the fight they brag on their elevendy billion DPS.
Also there are generally a lot of monks that utterly fail in maintaining their defensive buffs in general. Bad monk tanks are squishier than bad versions of any other tank.
One last thing. Monks are most squishy at the initial pull of a boss unless they precast buffs they built up from trash and/or have initial chi going into the fight. After this however they are fine. In a two-tank fight a smart monk will have 4 chi and elusive stacks saved for the taunt.
"For what is a man profited, if he shall gain the whole world, and lose his own soul? ..." - Matthew 16:26