I don't know where your going with this but Defense has 0 benefit in pvp. All defense skill will do is lower the chances of a player scoring a critical strike on you by 0.005% per defense rating so it is rather useless and makes no difference when vg has Naxx geared players with 40% crit rating anyways...
Yeah .. Close enough.
You gain 0,12% avoidance per defense skill (0,04 miss/dodge/parry) and -0,04 chance to be critted.
So, Qur, you read up on attack table and you'll have your answer
