It isn't though, yes if you go to "X" dungeon in a questline the same sort of things are going to happen, but if you do the dungeon at totally different lvl's the exact same thing's don't happen in the exact same way. I've went through a certain dungeon 2 times doing companions and once outside the questline all 3 times at very different lvl's 15, 27 and 40 and the "enemies" were very different in number and what they were, so I had to fight them in different way's. The character's were also different, pure warrior, battlemage and thief.
But really I try not to do alot of the same dungeons, forts or caves to close together anyway. I've done BOTI with every character just because I know it's bugged and I may later decide I want the house and it has to be done to get it. And I still find it fun to do. The only dungeon I find boring is the 1st one that has to be done in order to have Dragons appear, which I make a point of doing at as low a lvl as possible, so that it at least represents something of a challenge. But really I've done it at least 15 times, some characters not making it to far past their because I wasn't really happy with them.
I don't mind the actual dungeons - I don't personally feel they're much different at different levels - you can kind of guesstimate what you'll find at what level and it's still going to be the same type in the same positions - but they're mostly very well designed - some are pretty amazing - and much better overall than randomised ones. I like the little stories lots of them have to them too.
I meant the way you're going to see the exact same scripted events -e.g. you get to Riften. Hear Mjoll and her stalker talking about thieves guild. Maul talks to you. Then scripted conversation with mini task to get you handy potion for next part which is when Brynjolf walks up to you. Loads of the game plays like a FPS with the exact same scripted stuff at set points designed to wave quests in your face and talk you into doing stuff. Subsequent playthroughs would be more interesting - particularly from an RP perspective - if you were left to discover stuff by yourself by talking to people or doing things off your own initiative. Instead, Bethesda decided everyone is a cretin and needs to be told what to do. Then the questlines are linear and offer very little choice - usually kill this person and get item/don't kill this person and perhaps get different item. On top of that, the writing is terrible which makes it not worth replaying quests to enjoy the story. The strength of this kind of game is the freedom on offer, but Bethesda seem to have somehow made Skyrim into a claustrophobically repetitive environment I think due to these two factors - thinking the player needs to be constantly guided and prompted and their appartent ongoing refusal to employ any decent writers.
With a game this size, part of the joy should be stumbling across decent sized quests you never knew existed on subsequent playthroughs. But so much content is shoved in your face, you see virtually everything on your first couple of playthroughs and there's lvery little that's left for you to discover by yourself. You could totally miss the DB and thieves guild in Oblivion - that's virtually impossible in Skyrim. It's like they've become terrified you're not going to do everything on your first playthrough. Really bad design.
But the world is lovely and wandering around it is nice.