ME3's Co-op....
•Does not support Kinect.
•Will offer some way to deal with griefers. "Just know that we are putting systems in place that will let you deal with people that you don't want to be playing with."
•Has playable races besides Krogan, Asari and Drell that "you may not expect" - "they wouldn't normally be looked upon as characters who are for the fight".
•Will get playable character DLC. "We'll be releasing more and more characters through DLC later."
•Has characters that aren't involved in the single-player Mass Effect 3 campaign at all.
•Has leaderboards.
•Has its own Achievements, Trophies.
•Has matchmaking based on skill level - no word on how the latter is computed.
•Is on the main game disc. "Somewhat sizeable, but not so much that it affects the SP experience."
***•Can't be played locally - yet. "It is definitely on the table as something we might add."
***•Won't support user-run servers or offline severs "any time soon".
•Will be tracked by the BioWare Social Network website. "There will definitely be a lot of BSN integration. What the final
list of things is, we don't really know yet."
•Won't have friendly fire - to begin with. "Maybe later as some sort of modifier to the game, but not at release."
•Has "slightly different" - and "in many ways more" - weapon and armour customisation. "They are structured differently so stats don't play the same way."
•Has a story: "At a high level, Shepard is marshalling the troops on behalf of the Earth Alliance so you are technically fighting for the Earth Alliance. From a story perspective, a lot of these groups have come together as a loose fighting
force to stop the reapers therefore they don't fly the same type of banners that would have existed in pre- reaper invasion days."
***•Will one day be taken offline - i.e. there is a 'sunset plan'. "Yes, absolutely. We won't be taking the servers down until we realize that there aren't enough players playing to warrant keeping them up and when we do take them down, we will make sure there are options so the players who are playing don't feel abandoned. If anything is a good example, you can see today that Neverwinter Nights is still supported and we've kept a lot of our servers live on it. So I wouldn't be too worried about us taking down the servers any time soon.
Source-
http://www.eurogamer...3-co-op-details
Because of the star'd(***) reasons PLUS the fact that Mass Effect is a single player-driven game in the first place they damn well better add offline/split screen co-op or I and many will be biblically pissed off.