Well, I've got no problems with any of the balance or design of the weapons or equipment which are all very satisfying to use (except the SMG's which may as well not even be there, but it's not really a problem). The game types are all good fun and provide enough variety to keep me coming back. I think the maps are well designed. I also like how fast and busy it is and the various equipments and kill/death streaks always keep you on your toes.
I'm aware of the general backlash against MW2 in recent weeks but I really can't pay it any heed. I've been playing multi player shooters since the year 2000 and almost every major title has had the same backlash - Counter Strike Source, Team Fortress 2, Battlefield 2, Halo 2, Halo 3 and every iteration there ever was of the original Counter Strike. Halo Reach will be getting it's proper by the end of this year. If Battlefield 3 releases this autumn people will be raging over it how easy/hard/unbalanced/badly designed/1337 infected/how much of a "noob fest" it generally is by Christmas 2013.
I can appreciate people falling out of love with something and moving to something different but "disaster"? Stow that hyperbole soldier. There's plenty o' war to go around.