1. Main Quest - it's much better than the ones seen in Morrowind and Oblivion. (I can't compare it to Arena's and Daggerfall's main quests because I haven't finished them.)

2. Better Combat and has also Mounted Combat. Two handed weapons are wielded properly. Bashing.

3. Possibility and need to equip stuff (including spells) in one hand or another.

4. You can turn HUD off and the game is made in way it's fully viable to play it without HUD.

5. All skills affects in leveling not only the major skills like in Oblivion.

Enchanting had some thought put into it. Now in Skyrim it isn't exclusive to mages because you don't have learn a single spell. It also gives some use to the generic magic items that you normally don't even pick up or just sell. I was actually searching for enchantments. And enchanting with grand soul gems gave you more experience than with petty ones. Why wasn't smithing done like that? There's no reason to craft anything else but iron daggers cause it gives the same amount of experience as ebony cuirass.

Skyrim has a lot of improvements, but are they done particularly well?

I don't remember the exact patch version, but smithing and tempering xp gain did become item price based.

Wow, so now it's actually useful to make other stuff too? Glad they fixed it, but why wasn't it in the game when they released it? Was it because they intended it to be like what it was originally or it just took them that long to fix it?

I believe it was an oversight in the xp calculation formula, that managed to get through, during the "11/11/11" madness.

Seems most likely, too bad they couldn't settle for 12.12.12.