An interesting article by IGN.
Point 5 highlights the biggest issue the game currently faces, and one I think will take the shine off the popularity it has enjoyed.
The Issue: When I play Modern Warfare 2, it's usually for 2-3 hours. I've rarely made it through an entire play session without getting dropped out of a match at some point. Latency can be a critical factor in a player's effectiveness. Even the slightest variations in game speed between people can mean the difference between life and death. Modern Warfare 2 should be about skill, but quite often it comes down to who has the stronger connection.
The Solution: There's no one simple solution for this and I am not a technically savvy person. This one will take some hard work and dedication from Infinity Ward, but a balance needs to be struck so that players are competing solely on skill. I've never been dropped from more online games than I have in three months of playing Modern Warfare 2. And I have a solid connection. It's not good enough for the biggest game of 2009.
I am not technically savvy either, but I know the answer ... "DEDICATED SERVERS!"
Full article here