Experience should be put back to default. So people would appreciate higher levels more, because you have to work your ass off.

How about this... Make it so that the character must be on PK mode... Meaning, if you're on "peace" or "battle" you cannot PK nor be PK'ed. Would that be difficult to do?

This way, those who want to play for PK can do so without disturbing the ones who want to play in peace.