It certainly seems that nearly everyone agrees that casters in general, and wizards specifically are over powered to the point of being broken. I would like to know what exactly the reasoning behind this is.

Is it the versatility? Potential damage output? Ability to effectively remove an opponent from combat, or escape via spell rather then running?

Okay, nevermind, after writing that I think I answered my own question, so then new question: What changes need be made to bring other classes up to par or drop the caster down to level?