I don't see why, CoD2 without pam on publics was excellent, in competitive play PAM was needed because IW had not added any competitive support. In CoD4 IW has added more competitive support, but more crappy features on ranked publics. Next to that I have always loved the rifles in CoD2 and think a CoD game which doesn't have them is not really a CoD game.
IW created an awesome, flexible engine and built an excellent game on top of it. Best FPS game of the year and easily best multiplatform game ever (or this gen)
np : Apologize - One Republic