Because the game is more like Left4Dead-redux. To be honest, it feels like it's what Left4Dead should've been in the first place, but with the first all we got was a couple of (cool) game modes that didn't even work across all maps, requiring major patches after release.
They barely fixed the first game before rushing out a sequel. The first game should've been FINISHED upon release, with anything coming out after that fact being DLC that actually added to the gameplay. Instead they rushed out the first, promised massive support for it post-launch, then rushed out a sequel. This is totally uncharacteristic of Valve's behavior.
Hell, this makes Activision look good. At least the Call of Duty games are finished upon release, with DLC usually just adding more maps. Of course, each Call of Duty title actually has a two year dev time.







