Some interesting results from playing around using Rawr as a simulator for 3.0, for bear form. I couldn't obviously simulate what the new items were going to end up being across the board, so take this with a grain of salt, but this assumes that all leather gear has had every bit of extra armor removed from it.
- More often than not, pvp gear is better than T6 gear. In the case of the head, for example, the Vengeful Gladiator is better than T6. Same for the shoulders - and these turn out to be better than anything in sunwell as well. (this very much depends on whether agility is extra nerfed or not and what the avoidance rate is. Demontooth may still remain the best) The T6 chest wins out against vengeful but not brutal. The T6 gloves win against vengeful but not brutal. Tameless breeches handily beat T6 and Vengeful and Brutal.
- because of the higher stamina and strength, the feral versions of Sunwell gear tend to be better than the rogue versions. This is true for the leggings of the immortal beast, mask of the fury hunter, harness of carnal instinct, gloves of the forest drifter.
- some rogue gear is best in slot (depending on buffs, of course). Don Alejandro's Money Belt is better than Thunderheart Waistguard simply because of the two sockets.
- Thunderheart wristguards and treads remain the best.
- Mark of Tyranny becomes far better
- As does Pillar of Lol
This changes a bit if we get better than expected avoidance from agility. If that's the case, more rogue gear is best in slot. Quad Deathblow goggles become far better than any other option, for example. Belt of 100 deaths is stellar. However, given the nerfs to agility's coefficient at 70, I believe that this gear will largely be suboptimal.
So, similar to what we're seeing with the same iLvl items compared between pvp and pve, the PvP gear is winning out - largely because of how good stamina is.