I hate telling players "you can't do that", when possible I prefer to arrange the mechanics where I can say, "If you really want to, you go ahead," and watch his reaction as the rest of the players hurry to tell me they are getting waaay, waaaaay away from him.
Given that, I've been trying to houserule my game to where magic can be pretty much as powerful as you want it.... but you risk your sanity if you survive (even if you are successful), and in cases of really bad failure, you risk becoming the centerpoint of an explosion, and having your comrades take shrapnel damage from pieces of your bones.
So sure, you can have your "high magic" caster.... for just as long as you stay lucky. But the longer you stay lucky, the worse this story ends the first time you aren't.