first off, hundreds of games do.
and doom III isnt coop only thru live, the best way to play those types of games is to Lan them(sys link).
Youre talking specifically about Split screen coop, something I cannot and will not stand for. Its a huge reason why I lost interest in Halo 2. They announced split screen only and I was pissed. But that also means you need other people with other xbox's and/or 360's.
Games that task the system such as Doom III would fail miserably at split screen, thats why they didnt include it. I wish ALL developers thought this way.
Gears of war might be split screen coop, but I know for sure its Live and Lan
and thats ALL I care about when it comes to 360.
Marcus rocks!!!