Split-screen would have added SO much more to the game, (even if they had to reduce graphics, only in split-screen or in everything) and i would have to say alot of people will be reaaaalllyy bummed about it, but i highly doubt it will decrease sales, much, or at all. I remember playing games like warhawk with my brother, not the worlds greatest game, but hey! One person isnt sitting there the whole time going "yeah wow, that was cool...can i play now??" And then i remember playing Battlefield Bad Company and having so many arguments with him about who was gonna go next, and then having so many agreements on how AMAZING of a game it would have been with split-screen. I think, personally, that most games should have a form of couch co-op, even if it wasnt split screen. It just makes a games lasting appeal longer.