The first measure of linearity I feel is in the character creation itself, the first time you play it everything is great the flow works as you would want it you define your character as you go and that is great the first time now when I start another character it feels exactly the same for the wrong reasons I feel a very big sensation of deja vu in fact this feeling lingers for about the first 10 hours of that characters life. i think the big reason for this is because you don't create your class anymore therefor it takes time to get to the point where your character really starts to feel unique.
Another thing that gives this game a linear feel is the scripted events, for example the first time you go to riverwood and you go to the general goods store and start the golden claw quest the sister whatever her name is takes it upon herself to show you the way well I am not ready to go yet I wanted to go to the blacksmith first but that doesn't matter she just walks off into to the sunset talking to herself like I was with her it really takes you out of experience. And this isn't even close to worst case of this, who here fears going into a new town because you know what is going to happen yeah that's right you are going to accidentally trigger half a dozen scrippted events and you have to stop and listen to them because you only get one shot at hearing them and it is always the same with every character.
I not going to go real deep into this one because I don't think I need to but the sheer lack of dialog choices just ruins any changes you would want to make in the story with a new character. (or heck even your first)
I just hope this doesn't remain a constant in the TES universe it would really be a shame.

