They did mention bonus content and stuff. Maybe they make flashback levels based around key scenes from the first Mass Effect, only with Mass Effect 2's shooter gameplay. They could also release it on 360 and PC as DLC.
I also think this move is more so they can release ME3 on all three platforms at once, especially when they've talked up how ME2 to ME3 would be a more meaningful connection.
also, Dead Space 2 flying in space stuff looks awesome and the Crysis 2 multiplayer demo was boring.