It's a personal preference. Obviously with 10 million+ buyers per system the multiplayer is appealing to many, but here's things I don't like about it:
1. Rewarding players with added weapons/tactics for doing well. I found it annoying to be in the middle of matches struggling to get in the top 3 finishers when I would be alerted of a bombing run, or run around and see dogs were coming after me, etc etc. I prefer a level playing field, not giving good players tools to help them get better scores. That's like if in football, if you scored 2 straight touchdowns, they rewarded you by giving you 5 downs to get a first down.
2. Blocking off game modes until you gained enough experience in other modes. This is just plain stupid. If I like playing King of the Hill I shouldn't have to play a bunch of DM/Team DM matches beforehand. I didn't pay $50+ for a game where I am being forced to play "filler" matches in order to get to the ones that I want.
3. Getting better weapons with more experience points. See point 1. Give us everything up front.
As I said, obviously this is appealing to many players, but I'm not one of them. Given how some are projecting that MW2 will be the best selling game EVAR, I doubt my holding out will do much to affect the game's bottom line.
