I do this when I design websites. I mock up frameworks, stock photos, and plan for future content. What I come up with doesn’t always represent the final content. What I am getting at is just because that area is in the game, it could still be waiting for game designers, writers, and a cinematic. Also, with the ability to update by downloads, what you see now may not fully represent what they unlock when you download that expansion. Think about attention to detail as well. When your designing something your not going to build half now and half later. Let us use an office building for example. You wouldn’t build half an office building then half later when you need it. You would want to let people start coming in to open offices and slowly fill them up. There would be no unity or flow…and people pick up on things like that. When two things don’t match you will notice. So it is better to have that there now and fill it later than try and puzzle it together later with bonding glue and duct tape.