If we're talking melee only, I'm pretty sure the fighter will kill more minions in a twenty round period, and take less damage in the process.
True.
And given that the wizard has to rely on basic melee attacks with a much lower str, his overall chance to hit is much lower. But he can still smack an epic level demon minion with his staff and kill it the same as a suped up fighter with a huge str slamming into a demon minion. That is quite a strange idea to reconcile as far as imagining it.