By the trailer last night, I just have a feeling that it is going to be Treyarch's version of MW2, like WaW was to 4, so IMO, this will be a lot alike MW2, just different point in time and with a few of Treyarch's tweaks...
Oh, in case anyone missed it last night, the trailer can be found here...
http://www.callofduty.com/media/videos