I too get the sense it plays more like CS/BF than previous CODs, which isn't a bad thing. So far I am loving it, didn't really buy into the last 2 COD games but I will be picking this up for sure, I can see how deep the multiplayer can go with perks, create a class, challeneges etc.
I found out last night by reading one of the loading screen tips you can quick activate any c4 you laid by double clicking on the reload button whilst having your rifle equipped. Tried it out today and its great. Got quite a few kills by boobytrappin hot spots or door entrances and places where people might try to sneak up on me to stab me in the back