User blog comment:Argorrath/Activision confirms next Call of Duty for this year/@comment-2108119-20130210154658/@comment-1187559-20130210160121

Revolution would have only 1 gun, which is a musket, which takes about a minute to reload (maybe a bit less if it's rifled and you have a minie bullet), so that would sort of fall flat as an FPS. WW1, it was long, it was historical, but nothing really happened, so you'd have a pretty average campaign, and the MP maps would likely be meh as well.