think paladins still keep divine shield (12 sec invuln), but they are changing the other divine spell (forgot the name, you learn it low level) to reduce damage by 50% for 12 seconds - ie semi shield wall. Good for prot pallys.

and the idea of a tank for pvp is kinda pointless, you'd have an easier time just having 25 of the same class so all your buttons can map exactly the same. There will be little benefit to having a pally, druid, DK, or warrior as your main if your goal is just open world PVP.