Everyone says split-screen would come at a cost, i.e shaving away parts of the game making it less enjoyable. But what if the single player offline and the non split-screen online multiplayer were separate from the 2-player split-screen online multiplayer? (In terms of graphics/settings not game play)
So single player would still be the way it is intended.
Playing by yourself in online multiplayer (one to a console) would still be the way it is intended. So nothing changes for those 2 modes.
But then have the split-screen separate. I mean the PC version (should) already have the capability to choose game settings right? I.e Models, Textures, draw distance, Shadows, water etc... Low, medium, high, very high etc... So incorporate that for the 2P split-screen online multiplayer for the 360. I don't mean give players the option to fiddle with settings.
Just have 2P Split-screen online multi 'settings' set lower than 1p multi, to allow for the split-screen. Yeah the graphics wouldn't be as good, but single player and other people playing online (one to a console) would remain unaffected.
So that way it would give people the 'option' to choose to have a guest play at the expense of lower settings. But the people who don't choose to have a guest play can remain unaffected.
Just an Idea.