Skyrim is plenty of fun, but there is a lot of maintenance as well with leveling and selling vendor trash. To say nothing of the oodles of traveling and wandering. Depending on one's play-style, Skyrim can fall into a four hours of play, 15 minutes of fun rut. Plus as some mention, combat isn't perfect.
And dragons are a boring fight. For every character I've had, they've only been a big bag of hit points. My orc warrior-smith two-handed hammer wielder could berserk power-attack one down in two hits, or about a dozen regular melee strikes. My thief-archer could sneak attack (shadow warrior ftw) one down in about 10-15 arrows. And now my pure mage just fireblasts (with impact) one down with about thirty firebolts.
Snore.
Then there's the overabundance of quests. I have about sixty or so quests and yet I can't justify chasing them down without meta-gaming because I always have something more 'urgent' to take care of and by the time you've taken care of it, you've amounted another 5-10 more quests!
Not that the quests actually mean anything other than a bit of gold or the ability to take items from people who like you without being accused of stealing.
Then there's the whole, "Go anywhere, do anything!" Yeah, not. I still find MANY invisible walls, quest blocked doors (ie. you can't go here 'cause it'll ruin questing!), and on the flip-side, entire quest lines ruined simply because you jumped the gun and went somewhere you "shouldn't have"; well if I shouldn't have gone there, then it's not "Go anywhere, do anything!" is it.
For example, I almost had to abandon my thief-archer at 47th level solely because I got bored and decided to rob Riften blind on a burglary rampage. I had no idea that breaking into Mercer's house and taking his plans meant that the entire thieve's guild quest line would break and make it so it couldn't be finished or fixed. I had waited specifically until 46th-level to complete the thieve's guild quests because of level-based rewards capping out at 46, so that I could always use the Nightingale armour and bow without ever upgrading since I liked the look of both. That corn-holed my entire character concept and it was just lucky that I had a save at 43rd-level before I went on the burglary rampage. Of course, now I don't want to go back and play the missing four levels because I feel cheated.
It's not a terrible game, but after a few hundred hours of play, I certainly wouldn't rate it as highly as it has been reviewed. The bugs in it alone make it less than worth those ratings.