I know SWTOR has similarities to WoW but the thing thats really got me interested is the fact that each class has a Bioware storyline which plays out like Mass Effect but in an MMO setting. If its done well, and from what I've heard and saw from videos, it seems they're getting it right, then it'll offer tremendous hours of fun leveling gameplay/story on the different classes.
That sounds much more interesting to me in the long term than raiding/PvPing constantly once I've reached cap. That is something I've noticed from all the MMO's I've played, Everquest, SWG and FFXI being my favorites, is that the endgame was never as fun as leveling and progressing with characters. Throwing in the Bioware and Star Wars factor just means I could never pass this up
Hopefully Biowares answers to endgame content (I think theres an entire planet dedicated to PvE endgame) works better than previous MMOs I've played, but even if it is similar, I'm looking forward to leveling the different classes to experience the story more than anything.
The story is the only thing that is driving my interest at the moment as well as it being Star Wars universe etc. I want to see some progression from what WoW did. The story stuff is in the right direction but that's about it, and im not sure if that will hold my attention in the long run as im not the type of person to repeat things over and over for the sake of it.