A huge pet-peeve of mine in the current TES games is the fact enemies gain levels as you do. It creates a balance. Personally, I believe such a balance ruins the reward factor of the game. If I work my way to being a level 81, with 100 in one-handed, it ruins the experience if it still takes me more than one hit to kill a spider! Or if I'm fighting a Forsworn woman who's wearing next to nothing and I don't decimate her in two blows. The fact that enemies level as you do just means you never quite get the feeling of just being a god-like warrior, as if all your work is for nothing. The only element which works in your favour is the fact your health, magicka or stamina will be considerably higher than your enemies'. If I'm a master in the disciplines of magic or combat, very very few enemies in the game should give me a real challenge.
I feel that if enemies are set static levels, it means that working your way to a high level would be an invigorating challenge. It would also make the world more realistic in a sense that, when at a certain level, you know there are some enemies you shouldn't tangle with just yet. That should motivate you to be a worthy adversary for that enemy in question, whilst eventually looking back and saying "I used to get decimated by that type of enemy, now I own it!". The 'controversial' change I'd then ask for is to set level requirements for quests, so that you don't have a Dark Souls like experience...
The spirit of an RPG is the dedication to building your character, working your way to achieving the strength necessary to undertaking a quest.
What do you think?