Well before the patch max damage on fireball is 90 to the back 65 to the front if its surging. Don't know if it has changed. I can confirm this if you want me to hit you with it.

I am also considering air magic myself. Seems like alot of the good players coming in Andruk are using it. It does nice hp damage and alot more stam drain. Since the last patch stam drain is alot more important since it doesn't seem to regenerate as quickly. I'm currently using arrow shield to level it and plan on getting lighting strike for my damage spell.