How about the metamagic feat that changes elemental damage type from one to another?
So you could change your fireball to iceball or acidball but it either costs an increase in SP or maybe a number of turns /day. Not sure, open to suggestions.
I've noticed wizards always go for fire damage boosting items assumingly because fire is the most common type of damage available. I've never seen or heard of an ice or acid specialist wizard. Have you??
Your thoughts??