In several of the existing games there is a respec option, to respecialize your character.  Often times the character gets points each time they level that they can put into skill trees.  The respec removes all these points and allows the player to redistribute them.

So for MD, how bout a respec option for classes?  where a player can either complete a quest or pay some high fee and trade in their class object for a new one?  The fighter you are attached to, but really want them to be a monk, come into the office pay your fee and your class object is removed.  Head over to the monk guild and become a monk.