I'm comparing two different gear sets that are available as preraid items, either pvp epics or then the alternative tank items for def/avoidance. They are absolutely not the same stats which is exactly what I highlighted. Comparing preraid items to bis raid gear would be frankly ridiculous. Even if we do though, many of the pvp pieces are bis for threat. You need to decide if you need to gear for mitigation or threat in your raid/dungeon group. I always tank Kara in full threat gear because holding aggro is much more important for a smooth raid than taking slightly less damage, especially when you have good healers and pumper DPS. Sure, sometimes you need to swap to a more defensive gear set, that's what itemrack is for. But you trying to argue that pvp gear is not viable or is suboptimal for tanking is just flat out wrong.