I would personally like to see touch destruction spells come back. It would make being a battlemage a lot more interesting, I think. In between swinging your sword/axe/mace you can put your hand on them and burn them or shock them. The novice spells do an okay-ish job of that, but Flames is really the only spell you can power up a lot, and i'd like to not necessarily be pigeonholed that way. And speaking of pigeonholed... I don't want to go to a place where like 75% of the enemies you encounter are damn near immune to one type of magic. Being a frost mage in Skyrim is kinda painful at best, and actively faceplanting into a wall repeatedly at worst. Yes, there are ways around that, to an extent, but it's really obnoxious to have to worry about poisons to make one element as good as the others.