You know, I think that's why some people aren't enjoying Skyrim. They've come from games like the Witcher 2, which, whilst it's certainly a good game, is, to all intents and purposes, on rails. There are clear stages of the game that you go through at set times, with a handful of sidequests you can do on the side of the tracks.
The Witcher 2 certainly has better graphics too, but to have those graphics in a vast, sprawling, open game-world like Skyrim would require better PC's than most people have as far as I can tell. They look like similar games in a way, swords, magic etc, but they're really very different, and I think some people (And I'm not referring to anyone in this thread) have gone into Skyrim expecting something that it isn't and never was going to be.
That's not to say that games on tracks like the Witcher or things like the single player campaigns in games like CoD are bad, not at all. They're faster paced, more 'in your face', more cinematic, and there's a lot of enjoyment to be had in that. But if that's what some people were expecting of Skyrim, I'm not at all surprised that some would be disappointed with it.