I personally had no problem with the questlines themselves. I do have a problem with the way they were handled. A lack of freedom, consequences, benefits / drawbacks to your actions, shallowness all around, only one way to do something. These are the real problems in my opinion. I also wish they'd have gone deeper into the complexity of what's going on in the main quest. The Elder Scrolls is fascinating because of the metaphysics and philosophy behind its mythos. They had a lot going for them with Alduin, and the idea that maybe the world is supposed to end. Even one of the developers for the game, the one who writes a lot of the in game books, stated that Alduin is possibly a different aspect of Akatosh, different from the one worshipped by the people of tamriel, and that Alduin is the aspect of Akatosh that focuses on destruction and rebirth rather than creation and permanency. The implications of this could be astounding. They could have gone so deep with these ideas, and yet they just glaze over them and are never mentioned again. THOSE are my main problems. Not the stories themselves, but the SHALLOWNESS of it all.
I'd agree, but at the same time... I guess it brings me back to my point above. If I mix up questlines, it obscures the length of any individual one.
It'd be nice if they could be more extensive, but at the same time, that's a mighty workload. Perhaps we are entitled to that level of detail, but I think they handled the essential points of each quest well too. Like, everything is almost written as a cliffnotes/synopsis. The questlines touch only on essential points - enough to understand what's going on. And handled well enough that we get the point. It could have been worse, where nothing made sense, and they didn't touch on key points well.
The depth, I guess, is up to our imaginations.