User blog comment:AntiScootaTwo/Advanced Warfare Multiplayer Reveal Trailer released/@comment-6343006-20140811194458/@comment-6343006-20140811215800

The multiplayer is what determines a new Call of Duty, and no way can it accomadate a World at War II setting. It's become too dependant on customization, all those killstreaks and attachments and what not, and a WWIII setting simply has no room to facilitate that kind of gameplay.