User blog comment:Callofduty4/Achievements and next Spec Ops missions revealed via PC patch/@comment-220.101.130.141-20120420083515/@comment-92.84.46.33-20120421134831

That's the case when the main game fails to deliver on the SP side. IMO, the new games they release should focus on SP as much as they do on MP. DLC SP isn't really worth it they way they are designing missions now. MP maps have much more replayability.