OldFatGuy: Did you finish it?
Well... No, but that doesn't really say much because I'm notorious at not finishing storylines of Bethesda games. The only one I have actually finished out of my own volition* was the one of Oblivion, because I feel Oblivion had the most captivating questlines. I have also forced myself to finish storyline in Morrowind I suppose, but that really, really was me forcing myself to do just that a couple of months back because I love Morrowind.
Point is, I have never considered main storyline to be the most important focus of Bethesda's creation, and especially of The Elder Scrolls games, and the fact that you could always ignore it completely appealed to me a lot. I actually feel Skyrim is the worst in how it handles that - to get into the expansions, you need to finish some missions of the main storyline (at least for Dragonborn anyway), and after certain point, main storyline of Skyrim keeps reminding you of itself, which is something I didn't really like.
*I've learned that word in The Witcher 2! It's ploughing awesome!