One reason that I think TOR is so appealing is the limitless setting. WoW is all based, for the most part, on a single planet. Everything they do is somewhat limited by the restraints of design inherent with choosing such a restrictive setting. It is not only limited by lore, but physical boundaries as well. TOR can really get away with anything because space is infinite. Which means possibilities are endless because lore's impact is also minimized with it being set so far back in the history of Star Wars. Creatively speaking, Bioware has a much bigger canvas to paint on and more colors to choose from.
The approach to world design and end-game content is quite different. I enjoyed pve for the first time in a very long time in flashpoints. I can't wait to see operations and I have not had any desire to raid in WoW since launch of Cata. It feels like I am so much more involved in what happens in the story. You are helping shape the future of the galaxy. There are no Titans or Old Gods messing with things. The Republic and Empire do it all. It is "humanity" (aliens and all that idk what the collective would be) that decides what happens. No Empire teaming up with the Republic to kill a mutual enemy(I sure hope not). The main enemy is the other faction, other palyers.
It is WoW in space, but that is a good thing. Last I checked, space is fucking huge and limitless! Spaceships > flying mounts. World of Warcraft is very fitting. Imagine how epic Universe of Warcraft would be An expansion where you find that there is a set of new worlds for the Horde and Alliance to fight over instead of just a new continent. WoW is just on a much smaller scale. In TOR you are not special as an individual, but rather because you are part of the the most elite defense organization in the galaxy. You are demigods, fueled by powerful micro-organisms instead of a deistic lineage. You shape the story, not dragons, demons or magical beings. That is kinda how I see TOR, as if it was UoW. It makes sense to me at least, lol.