Luke Smith already stated that development of destiny happened shortly after halo 3. Also, cod are on three year development cycles which mean that what you are saying is absolutely impossible. The game went into full gear after reach, and there were hints of its development in odst. So no, black ops three was not in development before destiny. Ha-ha trust me, Activision wouldn't allow such a thing, just because they need to profit so much from what they spend, they need a yearly cod release