It would make no sense to have a game about WWII and then suddenly its Modern Warfare. They each have a theme:MW2: Present dayBO: Cold WarMW3: Somewhere in the near futureBO2: Far into the futureI have no clue how they would make another one however.
Call of Duty may seem like the same old stuff every time, but if you really consider it, a lot of hard work goes into making those games.we don't really appreciate it.