They should think about adding a system similar to the stance system from warriors in WoW. Make it so warriors can't tank unless they're in a defensive stance, and have the defensive stance lower damage done by the warrior by 50%~75%.

The biggest problem right now is how warriors can do damage, tank, and build insane enmity at the same time.

I also like the idea with the 1 healer requirement with paladin tanks and 2 healer requirements with warrior tanks.