Speaking of magic, I have an idea. How about that mages draw powers from an arcane realm but its based on their will power in addition to their intelligence. Basically, those with greater willpower can more easily draw up a spell but those who are more learned can use stronger spells. So while just about anyone can snap their fingers and draw up a spark or a candle flame, only mages can actually pull out a fireball or something.

I would also suggest that people have an innate "magic protection" that's based upon their will power.