I hope that, because you gonna make the game 3D, that it makes a difference where you hit an enemy. (ex. That if you shoot an enemy with a bow in the leg, it has less impact on his hit points than if you hit him in the head). It would also be nice when he's hit in the leg, he will walk slower and if he's hit in his arm or hand, he will not do so many damage with his weapon or even drops his weapon.

Dismemberment would also be great, but I don't know of the engine is capable of doing so.

These are maybe minor details for a RPG, but for me they give more fun to the game.