User blog comment:Bovell/Treyarch begins staffing for next project. MW3 announcement next month./@comment-3326681-20110405195824/@comment-3326681-20110405202258

Smuff you have a good point but how many games do you know out there have different developers. Developers don't usually use the same engine as other developers, Treyarch uses a different albeit upgraded version of IW engine. This makes it more likely that Raven will use a different engine.