A disappointed CoD1 player
Call of Duty 2 was a real let-down for me, a diehard CoD1 player. Aside from problems like infinitely re-spawning enemies in the single-player campaign, the multi-player game had less than the original version of the game. The original COD plus the expansion gave you a game with lots of maps, vehicles, several types of multi-player games, and the occasional interesting mod that actually enhanced the game. (The custom insults are funny for the first five minutes, and then they get pretty tired.)
In short, most existing CoD players would compare it to the state of the art at the time of the expansion. Unfortunately, CoD2 dropped the vehicles and many multi-player modes, rehashed some of the old, old maps, and added a couple of fairly blah new ones. For fans of the multi-player game, CoD2 set back the clock to the original game, added a better graphics engine (which, for Yours Truly, is a lot less important than the multi-player options), and somewhat new "storylines" for the single-player campaign. Speaking for this consumer, that's hardly a new full version of a product worth $40-$50.