Wonder if this comes out of pressure from the community. Feels like this "content" was planned for the game originally (originally being 1 long story with the survivors than broken into the campaigns) so maybe the pressure from the community made the polish this cut content and release it?
Yeah Keldarza, if you listen to the Dev commentary the whole idea was to have one single storyline, but they changed it later cos they didn't want players to feel upset that after making it to the top of the hospital, all of a sudden they had to start from scratch...
In all fairness I can understand the communitie's outcry because Valve was going to leave them in the dark, but then again the amount of content for the new game is immense, and in no way could have been added as DLC.