Finally a straight answer on what resilience actually does:
4. Resilience decreases your chance to be crit, and reduces the amount of damage crits do to you (both effects apply to spell and melee crits). Talents that affect crit chance still do what they always did, they increase your crit %.
well it has some pretty big implications for every class that isn't affliction warlocks or shadow priests, really
pretty much, but as every class appears to be getting it (on their pvp sets), it'll probably just work out to further blizzards goal of extending the length of pvp conflicts. Though it does have some (especially) negative impacts for talents that are specific to critting, (seal fate builds, mage ignites, warrior flurrys, etc.).
Assuming this works versus PCs (it appears to be on the pvp sets), this stat could have a substantial effect on frost mages, rogues and hunters, don't you think? Mages and rogues have already been concerned about the boost in HP everyone is getting making "bursty" classes less useful in PvP. Isn't this another example of negating burst ability?
Obviously, we don't know the mechanics of it yet, but I don't want my +50% chance to crit to become +35% because some warrior with 10k hp unbuffed (at 70 in the xpac) has 440 resiliance or something. Not that I lack faith that they'll figure something out, but I'm still a bit concerned about my, likely still, less hp, lack of "burst" and long-cooldown escape, range-making abilities. Frost will be fine, alot of the time with the ability to kite (2 classes) and what not, but a rogue?
I am having nightmares of 9k hps mages who can fuckup 3 times fighting me and still kite me to death. How will it ever be possible to burst down a paladin? Imagine a 4 healer defense in wsg, will it be impossible to kill? Will any class that relies on burst damage to kill select other classes be able to do anything?
I believe resilience is being implemented to reduce pvp crits specifically and solely, so that pvp becomes a test of skill and not crititude for some classes.
Resilience may work against mobs, in which case, tanks are going to find it much easier to control the damage they take, and defense is going to take a back seat. I expect few mobs will have resilience ratings, as this would allow us to have far higher pve raid dps compared to pvp dps. Blizz can also link new abilities to crits, further increasing the gap between pvp and pve functionality and dps.
Note that players will likely have zero innate resilience, so that means players in pvp contests w/o resilience gear will be susceptible to far more damage and effects. This will actually increase the gear gap between those who have it and those who don't, as the haves will take far less damage and have far more health than the have-nots. Hopefully, the first levels of pvp gear will be really cheap and easy to get, but from what's been leaked, I have yet to see such intermediate levels of gear.
I doubt the ~250 resilience on the priest arena set will negate the crit chance opponents have by alot. I'm expecting the part where resilience reduces damage on crits to be the good part about the stat, and the reducement in crit chance being sort of a nice bonus, but nothing you notice alot.
If 200 resilience reduces the damage taken by crits by 20% but only reduces the crit chance by 2% I'll be quite happy from a pvp point of view.
EDIT: Just pulling numbers out of my ass to prove my idea of the stat :p
Errare Humanum Est