GOOD STUFF:
1. LEVITATION.
I never used it much, as I never played a mage in Morrowind. But I would like to see it come back. Now that consoles are more powerful, maybe cities can be put back into the world space, as in Morrowind, and we can have Levitation back.
2. Incredible music.
I agree. I didn't like the music in Arena or Daggerfall but Morrowind and Oblivion had truly gorgeous music. However, with the exception of one track, I didn't care for Skyrim's music.
3. SHADOWMERE.
I guess I prefer the "real" horses in both games. I've had Shaowmere in both games and never used him.
4. Dark Brotherhood.
The Dark Brotherhood doesn't do it for me either. I thought they were annoying in Morrowind, they were boring and unbelievable in Oblivion. I almost kind of liked them in Skyrim, though.
5. Gods and Goddesses.
Yes, I think there is a rich and interesting background here. For the most part, they managed to avoid some of the usual cliches of some of the other fantasy roleplaying universes.
6. Oh yes, dragons.
I agree with this. I think Dragons are Bethesda's crowning achievemtn so far, in terms of creature design, animation and sound effects. I have been very critical of Bethesda's lackluster animation over the years but they really did a stellar job with Dragons. The first time I saw Alduin land on that tower in Gelgen was the first time I have ever been truly scared in a Bethesda game.
7. Some skills that are no longer there. Acrobat skill. You could actually jump all over the place, higher and higher and your acrobacy improved to a point where you could jump down from very high cliffs and not getting killed lol.
Acrobatics is actually one of the skill I would tone down drastically. By the time the skill was maxed out we could practically jump over houses. But in general, I would love to see Daggerfalls skills return. We have lost skills with each new game since Daggerfall (losing the most between Daggerfall and Morrowind) and would love to see most of them return.
BAD STUFF:
1. Annoying enemies. Mudcrabs. Sure, easy to kill but super annoying. Slaughterfish. Cliff racers.
I like Mudcrabs. They're fairly easy to ignore. Slaughterfish and Cliffracers, on the other hand, are harder to avoid. They did get on my nerves.
2. Having a quest where you should get something from the enemy after you've killed them. You kill the enemy, and the enemy is hanging from the roof or is placed under a bed etc.. And you cannot loot them.
This has never happened to me. I've been unable to loot non-quest enemies, though. When that happens, I just move on.
3. Morrowind's super annoying under water caves.
I completely disagree with this. I absolutely loved Morrowind's underwater areas. They were one of my favorite areas of the game. I adored grottos in particular. One of my gripes with Oblivion and Skyrim is that we do not have those wonderful underwater areas to explore that we had in Morrowind.
4. Mountains.
This didn't bother me. In fact, if I have one criticism of Cyrodiil it is that I can see practically everywhere. That tends to make the game world look small and removes much of the mystery of wondering what's around the corner or around the next mountain. Morrowind had a lot of mystery because we couldn't see it all at once. Skyrim's mountains restored some of that mystery and sense of scale for me.
BONUS ROUND: Oblivion DB quests are way better than in Skyrim.
I disagree. I prefer Skyrim's Dark Brotherhood over Oblivion's Dark Brotherhood. For that matter, I prefer all of Skyrim's questlines over Oblivion's questlines. The only criticism I have of Skyrim's guilds is that they are too short.