I love this game's story. But I also want to be able to play the story, and continue to socialize with friends while online. I love that I can go from single-player style RPG to MMO with PVP and OPS/FPs in a heartbeat.
If it wasn't an MMO, I know I wouldn't still be playing. I'd only play the story once, get some DLC when released, and that's it. Just like I did with Skyrim and others. I played the hell out of them, but I love that I can socialize and switch gears without changing games altogether.