There's no doubt that Call of Duty: Modern Warfare 2 will provide gamers with one of the best online multiplayer experiences ever, but if you're looking for co-op for the campaign mode, you'll be disappointed.
However, Infinity Ward didn't just forget to include it, nor were they being lazy in the development process. The bottom line, according to IW's Robert Bowling, is that they experimented with campaign co-op but in the end, it "ruined the experience." Instead, we'll get the Spec Ops mode, which is a "dedicated, mission-based co-op section playable either online or locally in split-screen," which sounds intriguing. In regards to the failed idea for campaign co-op, Bowling had this to say :
"We did it early on; that’s what Spec Ops started out as, as co-op through story. But it really broke the cinematic experience, took the immersion out of it, out of the story and the pacing and everything we’d spent so long crafting. It just ruined the experience we were aiming for, so we took it out, kept the single-player for that one player intact and polished it."
Essentially, the team decided to take all the best moments from the co-op campaign they ditched and implement those into the new Spec Ops mode. Bowling says you "really get the best of both worlds" in this way, so few fans should be complaining. Everyone is looking for co-op these days but let's just consider Spec Ops to be a new progression in the world of multiplayer; we have good reason to be optimistic.
Related Game(s): Call of Duty: Modern Warfare 2