My impressions on the game (away from all the controversy, SP side with only a bit of MP so far) are negative. I didn't like the CoD4 SP either. It is way too chaotic, there is constantly a huge number of bad guys shooting at you from every angle and the screen is always flashing and your camera is always shaking... it is boring.
What made the original Call of Duty so great was that there was down time between the set pieces that gave you a break - and even during the heavy action scenes there is pacing. With Cod4 and MW2 (And WaW as well) it is as if they just put the throttle all the way forward, all the time. There is no small probing attack on Pavlov's house before the large waves start coming. There is no manageable first few attacks at st. mere église and the lulls between the waves as the germans regroup, the same for pegasus bridge. It is just constant, "ZOMG THEY ARE TEH EVERYWARE!" and it resembles a shooting gallery more than modern warfare.
And about the single player campaign, what the hell does Infinity Ward think about the Russian army? During the campaign the russian soldiers had no standardized weaponry, and were using a whole litany of pistols, rifles and sub machine guns. It was as if they took ever single weapon out of counterstrike and gave them to the Russian army for the sake of "diversity," but it just bothered me that a major military force wouldn't have standardized arms or would send infantry into urban combat with tiny compact SMGs. Did H&K sponsor the game or something?
And the whole thing in Brazil, what the hell was that? Why are there swarms of the generic "local militia?" I literally blasted hundreds of them away and it wasn't very exciting, just boring.
By the way, the AI sucks. IW doesn't care that they are supposed to be highly trained soldiers, the enemies just run out into the open and stand right in front of you, spray and missing on full automatic. Once again, boring and not intense.
COD 4 was the beginning of the stupid console FPS style, and MW2 racks it up to a whole new level.