At the end of 2010 games like Assassins Creed Brotherhood and Need for Speed which offered unique online experiences that people we’re very happy with. Dead Space 2 released today and yet again it offered a new online experience. Last year Black Ops disappointed many gamers on the PS3, so they branched out and looked for better multiplayer experiences.
Highly doubt Force Unleashed would make a good multiplayer experience, but I have noticed the trend in games that never had multiplayer, but good singleplayer have good multiplayer. Little confusing, but should get my point.
I think more dev's are tacking on MP to try to battle piracy. Some are doing it better than others, but I can't see any point to a Mass Effect MP component, unless it was of the MMO variety. That could be worthwhile - anything else would be a waste imo.