Credit where credit is due, CoD4 had some pretty decent maps (Wetwork and Chinatown being my personal favourites) in both the standard game and the DLC.
MW2 on the other hand...I could have done better than that with the map maker in Timesplitters (in fact, I have done better than that), not because the maps themselves are bad (although there are things in them that certainly don't help matters) but because of the mentality of people who play it (you surely must have been on the recieving end of someone sniping from the crane on Highrise or someone camping behind the truck in Rust and so on).
Sadly, no amount of map packs or patches are going to fix this.