Yeah, I remember an interview where they stated that Online Co-Op was there from the beginning, but they had to make some tough decisions because of resource and time constraints [devs can't do EVERYTHING], and that was one of those things that got cut, because their testers found that it was more enjoyable to play Split-Screen Co-Op with a buddy on the couch rather to play Online Co-Op with some friends over the interwebz.
Due to the coding of the game, the question is "Is it possible to add Online co-op through a patch?" If they built it from the ground up with the idea for Online Co-Op to be implemented later, then that would definitely work. It's a grey area, but I too hope that they add Online Co-Op.
"Being single is easier on the gaming life, and the wallet."
