Wizard Competion Game

I have been looking at ways to adapt a Wizard vs Wizard game to other generes (it was originally two Necromancers battling over control of a graveyard) and thought the wizard battle at the end would be a good conversion and I was looking for advice/coments on some things.

Spells

So far I have ideas for Wall of Fire, Transmute to Mud(Earth), Wind Blast (which blows the objective or another player around the table) Rain Storm (which interferes with player's casting and other tests). Any other ideas would be welcome

Summoning Creatures
Another idea I had was using Magic:The Gathering for a base using the 5 colors and allowing the summoning of creatures to interfere with your opponent. I thought of the idea of being able to summon elementals.