It makes no sense! ESO is the first game I've played since WoW where I felt like there was an "RPG" in MMORPG. It had me caring about characters and events as early as level 5, something that even after a year of playing games like Rift and GW2 failed to do. The fact that I can make choices in what happens during a quest chain is just amazing to me as well. I also love the amount of freedom of builds with each class, you can do just about anything with anything.
The WoW expansions are cheap now. I know this because every other month my bf asks if I'm sure I don't want MoP because it's like $10 or something. :P
Sometimes I feel like maybe I should go back. I mean, I did play the game for 6 years and so far the average amount of time I've spent on an MMO since is just under a year. Other MMOs just aren't doing it for me for one reason or another. GW2's done the best of all of them, but I just can't stand the living story and there isn't anything else to do at this point.