Just because there are some environment art assets already in the game [i]doesn't mean the content is finished[/i]. Creating a DLC set in an environment that is already an open/contiguous space like the moon basically requires that some or all of the environment art for the DLC is already in place. Even if its not, like the Reef areas, its irrelevant. That just means they finished some of the environment art before the game shipped and have the hooks in and ready for the content to be dropped in. What isn't done? The mission scripting, strikes, the new raid environments and encounter behaviors, new enemies, pretty much [i]the whole thing[/i]. Some partially finished environments are a small fraction of the amount of work that needs to go into an entire DLC release with multiple missions, strikes, and a raid.