Well, I don't think they're going to add new terrain to the map itself. The map is already quite large and each server holds X amount of players. They probably won't add an "Add-on" to the map itself(excluding special events like Halloween or Christmas). Adding new maps isn't a good idea because if one map is better than the other, guess what happens? Empty servers.
But here's the map, I'm not positive that it's the official map.