Destiny has confirmed that there will be 5 comet dlcs. After each comet "mega" dlc we will see two smaller dlcs. After HoW we will see a comet introducing new subclasses and weapons. This comet will be hive oriented, and it will probably be oryx, one of the many hive gods. Then there will be forge of gods (Cabal) and another vex dlc. I think that all the comets will be hive based, but will be one of the hive gods for each one. Your idea is a bit large, but it would would fit in around 2017.