Ultimate Mage without Magic Blast? Weird.
Sure, Magic Missiles are fun, but Magic Blast is "You there. Die." attack. One shot, one kill: take out the annoying healer, summoner, boss, etc..
Only one point in Destruction? That is silly. Five points get you 50% damage boost. No need for +skill items, you hit like a truck and kill people dead.
Fireball is... all right... but you're much better off with Fire Wall, because sooner or later someone will get close to you...