My chance to hit should only be set based on my stats and the stats of the enemy, just like in any RPG. Making this system dynamic terribly weighs down the fights. It's unnecessary extra complexity, not fun, not interesting. I don't see how it adds depth to gameplay or tactics since it's hidden. This only reinforces the randomness. Randomness is very good, it takes some for a game to be fun, but here it's too much!
A turn-based game has the huge advantage of being able to be purely strategic/tactical (no need to be fast). But increasing the randomness with the AP system nullifies this advantage!
So in addition to weighing down the interface and the gameplay, the AP system destroys the tactical aspect of the game (in PvP).
