First, congratulations are in order. IMO you created a really good game!
The thing that really stood out with Skyrim for me compared to the earlier games is how the culture of Skyrim was so beautifully expressed and integrated into the experience. It gave a flavour that was nearly non-existent in Oblivion where culture were a mishmash of everything and thus, somewhat paradoxically, becomes nothing. It felt bland. Morrowind was better than Oblivion in that aspect but still nowhere near Skyrim.
As a student of social anthropology I′m fascinated by cultures and really enjoy such aspects of games when they′re well executed.
On the negative side, simplification was taken too far. Being an old school gamer I like complex rule-systems which really impacts the gameplay. I suppose it′s a matter of expanding the playerbase, still, it was somewhat decremental to my game-experience. In particular I disliked the removal of the old stats. They helped creating a feel of a character by the effects it had on the mechanics.
A minor nuisance was how weak the artifacts you find are. Almost all of them ended up in the house, and even the ones I used I wasn′t overly impressed with. Takes a bit of fun out of exploring when you quickly can make more useful stuff yourself by forging and enchanting.
Also I′m slightly miffed that my old account from the Morrowind development era is gone. ;P