These extra areas being locked is no different than the area in the tower, where the Queens emissary is, being locked from time to time. Does the area exist, sure it does, but there isn't always content to be used in that area, so it gets locked. My guess is bungie made the locked areas knowing they would add content to those areas later. For those upset by this, just think of the fact that the game could've been released with that content, but it would've delayed launch by six months. Destiny is not the first game to have locked areas, which were made in prep for expansion content.