I know it's been daring for me to not have a black and white opinion on this, but I am neither excited or repelled by the trailer of Modern Warfare 3. Basically it looks exactly the same as it always does, which I suppose on some level is an achievement considering everything that's been going on at Infinity Ward.
The bit with the tube looks cool, and the car and boat, chase but basic it's the same formula applied to slightly different areas of the world. But anyone suggesting Activision should something different are crazy. Even if they did most people would probably decide they didn't like it anyway - for better or worse Call Of Duty is stuck being what it is.
Even if it was 10 times less popular it wouldn't make any financial sense to change, let alone while it's the most popular game in the world. I don't think any of the footage is of the multiplayer but I'm willing to bet that's exactly the same as well and for the same reasons. But what's the problem really? It's not like Call Of Duty isn't a good game.