Hi,
Please read:
http://en.wikipedia.org/wiki/Game_server
Call of Duty 1, Call of Duty 2, Call of Duty: Big Red One, Modern Warfare 1, World at War, Modern Warfare 2, and Black Ops are all Listen Servers (for consoles) and not Peer to Peer topologies.
The only truly peer to peer game (using a literal definition) in the franchise was Call of Duty 3.
This can never be "fixed" because of this little thing called the "Internet" and how it works.
What we can and try to do is:
-minimize the upstream bandwidth required to play
-use the best networking prediction we can
-continue to have the Local Search only option
-improve the algorithm for how we choose the host
-continue to work with Microsoft on how they do Matchmaking
...among other things.
The common assumption that Dedicated Servers (instead of Listen Servers) will somehow solve all problems is not accurate. It's grossly over-stated as a cure-all. It causes new and different problems.
What many people don't understand is that (on the 360) you have to bounce and authentic all "Live" traffic through what is known as the xLSP gateway/proxy. In the simplest sense, it's a type of Virtual Private Network (VPN) between us and Microsoft.
All of the World at War stat servers (for example) run behind one. So does the infastucture telling you how may players are online; or the machine you get the Playlist from (etc, etc).
Reporting stats to a database server is one thing; sending game traffic through the gateway/proxy is an entirely different beast which will increase latency.
xLSP has policy guidelines and restrictions. The bottom line is that it both lets us offer a lot of stuff to you that Live itself doesn't offer (or has made generic to work with "any game" whereas we want to do something that works awesome for Call of Duty), but it doesn't exactly give us complete flexibility to do whatever we want either.
In Summary:
The game is not Peer to Peer.
Listen Servers, Dedicated Servers, and Peer to Peer games can never be truly "fixed." They can just be designed and developed to work better on the Internet.
Dedicated servers (for consoles) are not a cure-all.
We are MP developers and gamers, thus aware of what it is like to play MP games on the Internet. Including this one.
David 'Vahn' Vonderhaar