I enjoy Skyrim, still pick it up to play from time to time, but it doesn't share the same level of addictiveness as Oblivion and Morrowind, for me. Perhaps it's because I'm a bit older, I don't get as insanely excited for games like I used to, perhaps the level of expectation is so high these days that no game could hope to live up to the hype.
I played Morrowind for 250 hours, didn't finish the main quest. I played Oblivion for well over 300 hours, did almost everything you can do in the game. Closed 89 Oblivion gates, finished all guilds, and main quest. Skyrim I think I'm almost to 100 hours, and the same craving to finish everything and see everything just isn't there. I still chaulk it up to my age more than the game itself being sub-par.
Skyrim doesn't feel the same because Bethesda has over simplified the levelling system. Morrowind and Oblivion both required the player to plan a character at the creation stage. A mage with no magicka, fighter with no armor skills, stealth with no sneaking ability these were all possible and it made that character unique. You could intentionally roleplay a drooling sloth with no intelligence, you could pump up your luck and find grand soul gems where another player would find torches. Skyrim's health-magic-stamina system makes every character turn out almost identical, at least in my own experience. I pump up health to stay alive, move to magic to cast the stronger spells, and end off on stamina once the other two are juiced to my liking. Bethesda took the soul out of levelling up. No more agonizing decisions about should I get a bit more strength for melee, or endurance for health, or agility for sneak, what have you. Every character can be everything in Skyrim, and the game mechanics encourage players to mix magic with weapons. Not that I am against it, but if you take a Level 20 Morrowind or Oblivion character and compare it to a Level 20 Skyrim character the level of difference between the two is staggering. Sure all characters can become God characters in all the games, and all the games have exploits to make yourself invunerable, but if you play the game straight Morrowind/Oblivion feel like RPGs and Skyrim feels more like an adventure game with levelling.
I got more lasting enjoyment out of Morrowind and Oblivion because every new game I started felt different, whereas in Skyrim I don't feel I want to start a new game because there is no RPG element to distinguish my newest character from the previous ones. A Khajiit no longer has high jumping nor more speed than other races. Bretons and High Elves start with the same magicka as everyone else. Orcs and Nords and Redguards have no initial advantage of extra heallth.
The melting pot of all into one makes Skyrim more bland, less appealing as a game I can always go back to. I still play it, but I'm asking myself for how long?