really? I find mages to be severely under-powered due to how Magic was implemented...
When something meant to kill you is nothing but a mere annoyance, I don't think it's really overpowered.
Level up sneak so you can bash them before they toast you.
or
Build up magic resistance through perks, equipment, standing stone, etc. This will turn mages into little more than gnats to practice your swing on. (this gimps dragons though)
Personally, I like sneak. It leaves the rest of the game unaffected. One drawback is that guards call you a sneak-thief when you build up sneak, which may be role-play breaking for your character. The other possible draw back is that sneak can be perk demanding. If you can enchant muffle on shoes/boots you can get away with only five perks and be able to sneak up on the best of them.
Interesting post. I do see where you are coming from though. Mage enemies are definitely harder than fighter enemies in my experience. I think this is mostly due to equipment difference. Your character warriors are strong because of their super powerful equipments made from smithing. Without those legendary quality stuff they probably aren't more powerful than your mage characters. With enemies, when most of their equipment svck anyway, mage is the most powerful type since they don't rely on equipments that much.
I've had no trouble with them before except for Taron Dreth, who caused him to summon Karstaag cause dat boi was raqen meh