The main story foundations are built while giving you area-specific problems to solve. So instead of random NPC quests almost all the quests you get advance the story in some way. You will run a bunch of quests which don't seem to tie in with the main story but at points the Jedi Masters will reference the outcome of those seemingly unrelated quests.
I had moments where I had to make hard decisions and live with my choices. I was able to run one of the heroic instances with three other players. When the group spoke to the mission NPCs, everyone spoke with the NPCs. When I say everyone I mean various players would appear and ask a question to advance the mission dialog. There was a social system for this decision making process but I was not able to determine how it worked (ED: It’s based on a dice roll). However the game maintained that movie feel where a group of people were working to solve a problem.
Overall this game does something not many MMOs do and that is make you feel you are the hero of the game.