I've played Morrowind for the last seven/eight years and don't plan on stopping any time soon. That said, Skyrim's longest quests are no shorter than Morrowind's longest,
So let us replace "lack of lengthy quests" with "lack of sheer number and variety in type of lengthy quests" from the beginning of the game. I'll still never forget the visit-every-shrine quest from Morrowind, with only vague book hints in some cases of where to find them. And of course, no compass, directional pointers, or spells that magically show your exact path.
...the dungeons are far more unique and "individually defined",
I could have been clearer--I will be, now.
In Morrowind, each dungeon had a sort of mini-plot going. Creatures were chosen for it according to a large series of differing reasons. You might find eight named characters, six named thieves and two named warriors, guarding a pack of six slaves. Or a renegade mage and her pet atronachs. Or just a wolf pack and a few human skeletons. Or a tomb, with the odd skeleton or two, or a place crawling with mummies, or any number of other arrangements. In Skyrim, things are just in the dungeons, usually (though not always) without a specific purpose. Got it cleared? Miraculously, more will show up in a few days. I suppose we can blame travel agents. Morrowind was the way it was, though, in response to complaints that Daggerfall's dungeons felt very generic and cookie cutter--which they mostly are. Skyrim, like Oblivion, is a reaction to a desire to get the hack-and-slash Diablo/Sacred players involved. Nothing wrong with that. It makes more money for gamesas. But it does mean generic, reflling dungeons, as opposed to unique ones.
...and I can't even understand why you'd say there's little to do compared to Morrowind. Four hours has given you a skewed version of Skyrim...
And in my first four Morrowind hours, I'd barely begun to scratch the surface of the game, and realized that fact. I really liked those distinctive dungeons in Morrowind, the far more carefully developed landscaping, the three Houses at odds with one another, the numerous styles of architecture, the two temples and four religious paths to join (3 for the Imperial temple, 1 for the Dummer), upgradeable alchemy equipment, etc. Want to disagree with me? Fine; as I said, this is a matter of opinion. I feel no need to argue that your views aren't right--for you. Want to get into an argument that only your view is correct? You might want to find someone else, since I have no interest in that.
Great image you linked to.
But I've seen no one suggest that's typical. What I've seen of Skyrim--and read of it--so far doesn't lead me believe it it possesses the visual variety in terrain, architecture, or plant life in Skyrim that Morrowind has.