I fast travelled in oblivion all the time, and I believe the reason for that is because the world did look all the same, and it wasn't really worth seeing all over again, so once I found a place I would just zip line strait for it via fast travel. Here, I think I know exactly why I'm not using it and that's because the world is just so detailed and beautiful. You dunno what your gonna find, so many random events could happen like finding a guy whos been eaten to death by pit wolves and then finding a note on his body with orders to return these wolves to the arena. Or a member of the dark brotherhood who has a contract to kill you. Or maybe even finding a broken down horse and carriage with some sort of crazy circus clown who is supposedly carrying his dead wife?
And these are just a scratch on what is a very deep and very large service, and it just rewards exploring! I don't think it would of worked quite as well if the gameplay and systems didn't work together so well but they do and it's just amazing.
So do your self a Favor and avoid fast travelling, you really will be rewarded for it! (plus it's just fun to explore!!)