I don't see the fact that some dungeons that I havn't done in the first areas are now very easy for me as a problem.
It's part of the design. It makes the world more believable. Because it does not revolves around you.
In fact I see it as a quality, because it offers me two possibilities : to go back there when I want and see the fruit of my effort, since it will be a cakewalk now. Makes you feel strong

, or simply choose to see them when I'll create another character. It's great to know that there are so many dungeons that I can create a new character and virtually level up in completely different dungeons.
And it add more variety. Dungeons are very well implented in the world. Where most of the civilisation is, dungeons are easy. Venture into regions where there is no towns at all and it becomes more dangerous.
Something Oblivion fails to provide...
In any case, I'm a roleplayer, my character doesn't do every dungeon in the world, he's kinda lazy. He'd rather bathe all day in erothin and cook good meals with the meat of the wild animals he hunts and plants he harvests
