According to Activision 60% of CoD players exclusively play CoD and no other games. Consider that. That remaining 40% is still likely to drop by and play Destiny every once in a while. Even then, Call of Duty and Destiny are both published by Activision. They aren't designed to compete with each other, it would be pointless. Nothing's going to change. The nerfwhores are going to keep calling for nerfs and the "earners" will keep complaining about Xur. There will be no significant impact on the playerbase as a result of Advanced Warfare's launch.