This is an idea I had that I find very enjoyable because it increases the challenge of the game and forces you to be more creative.
The idea here is that you create a Specialist Mage and limit yourself to only using spells of that chosen school. If this seems too much, you could add in one spell per level outside your school (probably necessary if you're a Diviner). On the one hand, this cuts down on a Mage's versatility, which is kind of the big appeal over a Sorcerer. On the other hand, it can be easy to get into a rut of only using certain spells - especially if you've been playing the game for a long time - and this pushes you out of that.
I personally tried it as a Transmuter, and it was a lot of fun. I also discovered that in BG1 - not BG2 and, sadly, not BG:EE - Shocking Grasp was actually a pretty rad spell, as instead of turning your hand into a weapon that you had to hit with, it was an instant-hit, targeted spell like Vampiric Touch.
Anyway, I recommend giving it a shot. Invoker and Necromancer are probably the easiest. Diviner and Abjuror are probably the hardest, and the rest are all somewhere in between.
Give it a shot! I think you'll enjoy it. And if you're really looking for something new, do a party of specialists: CHARNAME (preferably as a Transmuter or Abjuror), Xzar, Edwin, Dynaheir, Xan and Quayle.
Doing this with a Wild Mage seems silly, though. You'd just be NRD'ing more NRDs, hoping that something good will happen.