With MW1 there was some annoying run and gun cheese but for the most part sniping, rifles, SMGs, even LMGs were viable gameplay styles. They basically said "screw fairness lets make insainly overpowered kill streak that devastate. (While maybe its realistic to get destroyed military hardware that you can't do anything about but it doesn't make for a fun or balanced multiplayer experience). Also the run and gun cheese basically became insane due to unlimited sprint and next to no accuracy penalty for running at full speed and then firing a machine gun full auto. Unrealistic cheese like akimbo shotguns, super speed knifing, etc basically ruins any of the fun CoD use to stand for (semi realistic combat that wasn't run and gun). Besides the unbalanced cheese and unrealistic combat there are a ton of glitches, crappy matchmaking system, and at times lag issues.
I liked MW1 but MW2 ruined it for me when 80% of the people in each game are noob tubing, knife running, or akimbo shotguns. Sorry but this isn't the same style of game that I so loved from CoD 1 up to and including CoD4:MW.
Spec Ops btw is great fun and the single player campaign is fun but the plot is rather shitty.