If Chameleon, Invisibility and Control spells in Oblivion, made Illusion "too powerful" and ruined your fun then, DON'T USE THEM. Have fun however you like, without ruining it for others.
I liked playing a mage/illusionist, cloth wearer, with no weapon skills, on the hardest difficulty. And never even mastered Destruction once (it just got you killed on Very Hard mode). And I had FUN using those powers. I played Oblivion over and over. I made the mobs kill each other then I'd conjured daedra and undead, to get the remaining ones, and just disappeared. It was so much fun. I'm very sure there were many, many ways to defeat the game on Very Hard mode, but I didn't want to learn them, because the way I did it, was just so much fun.
This rant is in response to some buddies saying, "I'm glad they nerfed Illusion, it was just so over powered". How can it be? If it's not fun for them, then they should adapt the play-style that is the most fun, just naturally. It's not like there was only 1 way to play the game. We have another buddy that said "hm...I think I'll play it unarmed, with only mysticism and restoration, this time..."
I didn't want a new game, I wanted the old game, with better graphics, and new story-lines, set in a different place. That's what I was hoping for, and, foolishly perhaps, was expecting. And I feel let-down.
Ok, /rant over
sorry.