I should preface this by saying the multiplayer in call of duty games does very little for me (putting me firmly in the minority on that one) and that the real draw for me has been the campaign of the Modern Warfare games. It's a pretty wrote subject, but personally I really dislike the Treyarch developed call of duty games, while loving Modern Warfare. It's difficult to properly pinpoint what exactly turns me off of these games, but a generally hokey story is a start. I really gave a shit about the characters in Modern Warfare, and what they were doing while on the other hand I absolutely don't care about anything going on in black ops. Granted, I have only played a few hours of the world at war and black ops campaigns, but considering the length of these games that's probably a suitably substantial chunk. 
 
 I suppose that my main problem is that I can't quite connect with the gameplay so to speak. It's a bit of a wishy washy statement to use, my analogy is that the gameplay feels like one of those terrible Steven Seagal action movies, where everything is very transparent in that you can see actors intentionally falling over on cue, rather than seeing a person killed in a realistic way and acting accordingly. More specifically, it feels like there are a lot of moments which really should evoke that "OH SHIT!" response that you might get while rappelling out of a Gulag with a heroic, mustachioed SAS badass, or being swept up by the pressure wave of a distant explosion while your hard charging GI buddies scream "HOO RAH!" & "GET SOME" generation kill style. In terms of actual gameplay, scripted sequences feel very obvious and the ai (in between spawning en masse around corners on cue) will often act in very odd ways, like charging past numerous npc's in order to attack the player specifically or at other times being completely oblivious to your presence even whilst being gunned down. 
 
At this point, I'd like to point out that this is my opinion and that I accept that you may disagree with it, or that I may simply be wrong. I want to ask if you agree that there's something iffy about these games, or if you think that my quarrels are just constructs of my imagination and that there really isn't a discernible difference between these games.