Yeah, I don't really like on-rails shooters either. I'm just saying that kinda reminded me of one because of the scripted enemies and all that... plus if you think about it, you have to head in a single direction so its not much different. Sure you can move around somewhat, and there are different types of cover you can choose to hide behind, but its fairly limited all the same. Actually, the Black Cats mission in WaW is an on-rails shooter in every sense, because you're on a plane firing a machine gun and you have no control whatsoever about how the plane flys. So that really is on-rails by any definition.
But then again, the real draw for me to COD type games is always online multiplayer. I just happened to be doing the solo campaign in order to get all the trophies. So far I have about 40, out of a total of like 60 or something...