i agree with pv2 as to what makes it a bad game
however i would add to it how much crap and cheating goes on online
offline multiplayer sucks (the only way i play multiplayer these days)
story sucks, saying you never know whats gonna happen next
does not even make a case for it being good.
it continues? no it repeats (number of cod games are based on WWII: 10)
it repeated TEN FUCKING TIMES! TEN, not one not two not three not four even TEN, fucking TEN!

its shallow, you switch characters too often for any meaningful character development
every good mission in modern warfare was repeated in mw2 (the sniper mission being the most obvious)
the game uses "shock and awe" type of things to keep you from noticing it sucks
oh and online play, its a bunch of bitchy twelve-year-olds hiding in walls.