I had a conversation with a friend about this exact topic a few days ago. While I played at launch, I took a year off right before Makeb was released. I did notice many changes, mainly for the better.
The points I brought up in the discussion mainly revolved around SWG(My first MMO) What captivated me in that game was how OPEN it was. Most of the time you could see a fair number of players in major cities like Theed and Mos Eisley. There wasn't any real story based system so what did people do? They worked together and created their own content and stories. The PvP battles were fun when you got a large group attacking a player city. If you didn't want to fight, you could go explore, I remember people going nuts when they found a DJM, or first stumbled on the DWB. You could craft, gather resources etc. In short, it felt like a universe.
I don't mind having linear stories, in fact I enjoy those. I think one thing I had hoped for was more open world/sandbox elements in gameplay. When you look at it, you hit level cap, why would you go back to Tatooine, Balmorra etc? Other then to help a guildie maybe or achievement hunt?
To this day one of my most memorable moments in gaming was the destruction of Restuss in SWG. It was a cool event to see unfold. If SWTOR could do something to bring some life back to ghost town planets, I think you may see a few people come back and see the good changes that have happened.
All in all, SWTOR is a solid game, I don't want it to be an SWG clone, but seeing some elements from it be implemented would be cool.