I recently created a new soveign with life and air spells. Needless to say, he was very weak in the early game. making those spell types unattractive, at least at the lower levels.
I remember back in the orignal AD&D, a magic user could choose from a pool of spells of any kind. Thus when a MU made it to the 5th level, he could chose his first 3rd level spell, which could be fireball, lightning bolt, or cone of cold (among many others)
His choices weren't restricted to a certain element, or school of magic.
I think this would make the game more interesting and varied.
Also, it would reduce spell duplication (e.g. cloud walk, vs. call of the titans, or the fire bolt vs, the death spell bolt, etc)
My 2 cents.