-Guards are not telepathic savants that can see through walls and instantly teleport to wherever it was you stole something. (People can still see you and call the guards rather quickly though)
Also, if you kill someone in the wilderness and someone sees you, you get a bounty. However, if you kill all witnesses, the bounty goes away (I know this from slaughtering the thalmor).
I find Skyrim to be a significant improvement over oblivion in the gameplay department.
The lack of class-based builds eliminates the issue of intentional manipulation of your level.
Enemies scale, but not so much faster than you that you feel stronger at level 1 than level 20 (also see above comment). In fact, I am level 39 right now on my main character, and I feel like those levels have actually paid off (Firestorm is amazing when you cast it for practically nothing).
The game is still buggy. In fact, I have had more bugs in skyrim than I did any other elder scrolls game. This is, in part, due to the fact that I've been pretty lucky with bugs in bethesda games until now (My only fallout 3 issue was that the game did not want to close properly all the time).
Melee feels much more rewarding in skyrim than other elder scrolls titles. If you attack an enemy at low health, or would deal a killing blow, it will actually show a special animation. For example, if you play as an assassin-type character and kill someone by sneaking up on them (if what my friend told me is correct), you will actually grab them and slit their throat. In my case, if you kill someone with a greatsword, you will shove your sword in their gut and throw them to the side.
Dual wielding spells and weapons makes things interesting. A good, well-rounded character who focused on sword-and-board could bounce back and forth between shields and wards to better protect them from their respective opponent.
My biggest gripe is that it feels like a lot of questlines are too short. 4 quests in and hey! I'm archmage of the college (not really 4, but it sure felt like it). In oblivion, you had to spend a good while working towards getting to archmage. After that, you can do a lot of small, side missions for that group, but a lot of those smaller ones are "go here, get this" or "go there, kill that." All the main stuff has good story and background, but it stops before it goes to smaller side missions.
Overall, I would say its somewhere between oblivion and fallout, but much more oriented towards fallout.