I totally agree! I'll definitely be going back to Oblivion...
...right after the game unglitches my uncurable vampirism, gets rid of the strange green/blue hue under every character's eyes, gives me a separate panel for keys so I don't have to scroll through all 324 of them just to get to a repair hammer, makes companions more useful, adds an actual use for sleeping more than 1 hour a day, makes Oblivion gates actually worth entering, and adds something to do after I've gone through all of the most interesting quests.
Skyrim is - technically and content-wise - a better game.
If we want to talk about the UI, then please explain to me why I need to sort through eighty-billion books, deeds, and keys just to get to my repair hammers? Sure, I could hotkey it (360) but that's a spot that could be used for my chameleon spell which doesn't make much sense considering I could just use invisibility.
The GUI - save, possibly, the map - is much better (in my opinion): essential things are finally separated (potions from ingredients, keys from misc, etc.).
As for the "oh boy, a different enemy avatar!" comments, please. You and I both know that if they replaced the dragons with - say - a rhombus, you'd call them out for adding something that doesn't fit. Yes: avatar and enemy behaviors do matter. That's why the dragons are an improvement over - say - your companions from the last game. Sure, they're not the most difficult things in the world, but they add a flavor to the game that's enjoyable.
As for perks replacing skill enhancements, what's the difference? They're not different than unlocking different abilities at the apprentice, journeyman, expert, and master stages except that there are more to choose from and many appear in between those classic designations, allowing you to better define your playstyle. Additionally, there are more perks in Skyrim than there were bonuses in Oblivion.
Most of the OP sounds like an appeal to nostalgia, if nothing more than crying over elements that are pretty much no different than Oblivion.
TES IV had a worse UI, worse character creator, and was technically inferior (less draw distance on characters, constant loading stops, constant drops in framerate in the bigger battles, etc.).