What more needs to be said about the biggest console franchise in gaming history? Most people by now have played Call of Duty, or COD, or have at least heard of it, and if you haven't, you've probably been on another planet for the last 3 or 4 years. Every year, another release that breaks the previous instalment's records. Since the release of Call of Duty 4: Modern Warfare, it's popularity has seemingly increased ten-fold every year. Therein lies the problem, how do the developers keep making a new game every year, that is essentially the same thing, and keep people interested, without changing the concept too much, but having to add enough fresh content to keep people coming back for more?
This question is certainly not answered, in full at least, by Modern Warfare 3. If one can manage to forget about all of the preceding COD titles, and think about MW3 as a standalone game, then you would realise that it is an awesome title, loads of fun (when it gets it right, that is), and that Infinity Ward have done enough by listening to the COD community (for once) to keep most people interested. The single player campaign, whilst very brief, is full of action and variety, and the overhaul to the Spec Ops game mode actually makes it worthwhile playing (and in my opinion, more fun than Zombies).
However, these are not the heart and soul of a Call of Duty title. Online multiplayer is what made COD the premier FPS on console to begin with; it is what every follow-up release is to be judged by, and every other FPS to be judged against. The decisions that Infinity Ward and Sledgehammer have made in relation to the online component are mostly good ones. More emphasis on gun-on-gun gameplay, less on killstreaks, and the removal of certain things from the game that were unbalanced, should have, in theory at least, given us the perfect COD. The problem is though, and this relates more to the community than the developers, is that no matter what gets removed or nerfed, bad players will always find something to exploit (Akimbo FMG's anyone?). The onus is now on Infinity Ward to keep listening to the community and releasing updates, to keep everyone happy with the game - something that they have not done with their previous Call of Duty's. To their credit though, they are doing well with these updates so far.
The single biggest problem with online multiplayer right now though, for me and millions of other players, is the addition of "lag compensation". Any first-person shooter that does not used dedicated servers runs off a connection to a "host" - the player deemed to have the best and most stable upload connection that every other player in the lobby can connect to. In previous games, this could often result in a sometimes unfair advantage to that particular player. Whilst this was annoying from time to time, it was never a problem as everyone knew about it, and it was only one player that received the benefits. Now, with the addition of lag compensation, good players with decent or better connections are being punished, and bad players are being rewarded.
The idea is that it was supposed to reduce the advantage that people with a good internet connection received over players with poor internet. Whilst this is a noble thought, all they have managed to do is almost completely ruin the game for anyone with an above-average internet connection (myself included), as it will often give everyone in the lobby an unfair advantage over you whilst playing.

Now I'm sure that everyone else that is having this problem is not going to downgrade their internet just to get on a level playing field. If you are like me, you have probably just stopped playing the game. Such an issue can lead to this result, even though I am a COD tragic, I love the game, I love the franchise, but it is very, very frustrating to play, so rather than put myself through the punishment, I've decided to stop playing until it is fixed. Whether or not anything will change is up to the developer; even though they have been efficient in supporting MW3 since it's release, their track record with previous games doesn't leave me with much faith in them. Overall it is still a great game, and if not for this one issue, it may very well have been the perfect COD. Will they listen to players and fix this, helping it become as great as we all know it can be? Only time will tell.