There's a lot of improvement over Oblivion, but after an extended play session, several aspects of the game feel half-assed and poorly designed or balanced. Don't have too much time for the forums this morning, so I'll just quickfire some of my complaints to blow off a bit of steam:

EDIT: Discovered after posting this that Conjuration increases VERY quickly with the use of the spell Bound Sword. The mechanics of Conjuration in Skyrim appear significantly different from previous TES games. SV suggests that summoned creatures increase the Conjuration skill by an amount relative to the amount of damage they deal in combat. I'll leave my original comments below, but bear in mind the above when reading (and see later posts for more information).

Skills like Conjuration and Alchemy (for example) raise very slowly and require constant grinding to keep pace with other skills. That's not fun or "natural" (as some have called Skyrim leveling). If you don't grind these skills, most of the associated perk tree will be unavailable. Building effective characters seems to consist of grinding a particular set of skills and avoiding increases in other skills to maintain a balance of combat effectiveness and level. Perhaps it'd be better if perk requirements were level-based instead of skill-based, or if skills increased at better or more consistent rates, but as-is it feels poorly designed.

Starting skill levels are influenced only by race. Despite the influence of Fallout 3 on the game mechanics, there is no option to tag particular skills for better starting levels (a simple element that would have given a sense of actual character background).

Cooking might have been a useful subset of Alchemy if better implemented, but instead it seems to be a simpler version of Alchemy that produces health and stamina boosting meals but doesn't raise the Alchemy skill. Tanning and smelting don't seem to raise the blacksmith skill. Alchemy seems to net a disproportionate monetary gain compared to other skills. Enchanting and Smithing seem to require non-immersive grinding to be of any real use. Perhaps all three crafting skills activities could have been better implemented as perk trees with no associated skill (removing the grind aspect, unlocking better items to craft for each perk assigned, perhaps with level requirements for perks instead of skill requirements).

Marriage is simple (which is good... it's neat to be able to "decorate" your home with a spouse but unnecessary to implement "wine-and-dine") but seems half-assed in implementation: Rather than an open system scripted to check "can be married" and disposition variables and allow any available character to be courted, it seems that choice is limited to a small number of premade spouses.

Loot and shop items are still leveled. Need I say more?

Companions still aren't "essential" (not able to be killed) but are still suicidal and stupid.

Random quests ala Daggerfall are... well, let me just describe one: "Go brawl this guy into submission. Don't ask why, cuz there's no reason, no story. Just travel halfway across the world (or maybe just walk across the street, cuz it's random), beat the guy up, and come back for your prize." The mechanic might have been cool with complex scripting and interesting scenarios, and it might work better with other types of quests, perhaps... But it seems another half-assed implementation in my experiences so far.