I have a player who is a fairy cleric/wizard that plans on eventually taking the Mystic Theurge as a prestige. Who here thinks this prestige class is too powerful? What are the weak points that keep it in check/balance, if you think there are any? What would you do to bring this powerful spellcaster back into the general level/power of a group, if, in fact, this person is too powerful?
I'm looking for an answer besides don't allow the Mystic Theurge prestige class. :-)