I've always thought AC should only be there to affect PVE. It was irritating not being able to hit cell as a young warrior because he stacked AC to the optimum o.o
Didn't understand why some should have 'god mode' (you could call it that since they can kill but can't be killed) over lower levels, the HP difference alone should be enough.
It'd be nice if you gained speed every level

- level 110 = +1.100