World at war will be quite different. World at war also supports the same kind of server system cod4 does.
We also have a world at war server. I think the biggest thing for me in games like this ends up being who you play with.
I don't think it is possible to have a mw2 server like we have with cod4.
Waw is a cool game with the right people. It wasn't given enough attention or time. I would say world at war is underplayed. I haven't played mw2. I have played world at war and have noticed that the features of the game are still highly undiscovered by the majority of the players. This is unlike cod4 or most games wtih competitive player populations in which almost everything there is to be figured out about the game has already been figured out.
Waw still suffers from a lot of problems, though. The maps are not especially well. A lot of the structures and designs of the maps seem unnecessary and not well thought-out. However, they look good and some of the maps are huge.