Edit: Skip to the last part of the post if you don't feel like reading.
1. Skills increase too quickly: In my opinion, there should be kind of a class system to restrict just how good you can become at everything. It's not really realistic that your character can be a master at 100 different things that are completely unrelated to one another. I became a master Blacksmith in like 30mins.
2. Lack of combat versatility: Combat feels great and brutal, but I had hoped I could make a character who could mostly avoid confrontation with eloquent speeches and personality. In the end, there is only one skill related to personality and it's practically useless.(Yes, I would love spears, crossbows, throwing knives, darts and setting up traps)
3. Races are meaningless: That's the one thing that killed it for me. I wanted to roleplay a barbarian, unarmored Nord for my next playthrough but I gave up. There is no unarmored skill and my Nord didn't feel different from my Redguard. Something that really breaks it is the fact you DO NOT see your character in the inventory. I don't know for you but it reminded me I was playing as a specific race and I enjoyed looking at my character in the inventory.
4. Overall lack of roleplaying mechanics: Frankly, I don't care about jumping higher, however, I do care about running faster. Before Skyrim came out, I had planned on making a nimble Khajiit who was a great talker. A rather weak fellow who would settle matters with his tongue and run away if he couldn't. I couldn't do that. I had also planned on making a uber strong Orc who was terrifying to the masses...couldn't do that either. Like it or not, attributes and stats help us define our characters better, it makes them feel more different and if the stats reflect in the gameplay, all the better.
tl;dr: Skyrim lacks a roleplaying factor, there isn't much difference between the playthroughs. You end up choosing mostly the same skills because some are just too useless. There are basically three builds, Warrior, Thief and Mage. Not many choices and combining them doesn't feel that different either. Some wanted to create a martial artist or a faithful paladin. I for example, wanted to create a wise monk with good hand to hand skills and speech but yeah, no unarmed skill. I find the roleplaying mechanics severely lacking. This is a great game but I don't know. It kinda lacks the replay value a pure RPG has. I really don't feel like playing another character because I know he'll end up roughly the same as my last one.
That is all. I hope Bethesda fixes this in the next Elder Scrolls game. More skills and roleplaying mechanics to add replay value would be great.

