Thing is. Since the areas are already there(some with enemies) they could have easily have included them in the game. These areas were already in as far back as the alpha. Which means they had plenty of time to actually finish it all. (If they aren't already finished and they're just waiting to release the rest of it to the people with the expansion pass) These missions and areas should/could have been in the final game but were most likely cut to be sold later as DLC. Looking at the lack of content Destiny have right now it could have used this content on release instead.