Well actually, if I keep it just the terrain, other people can get in on making those things, or converting certain tiles from say rural or forest over to the same textures as this. I don't want to get into making a huge variety of buildings I might never use, and that the majority of users will never use, especially if they can just as easily make their own conversions from rural or forest.
For instance, I have heard that Spain has some badlands regions, and I would bet that at one time the locals put up some stone buildings in the area, or the Romans even put up non-local-made buildings. So you might consider taking some of the spectacular building designs from something like TNO city and porting them to the badlands, and even paint them to make them fit in with the rock texture.
I tend to keep 3 stone henge, a few dolmen, some grave stones, worn roads, some world-specific bridges, and some teleport circles around and move them from tileset to tileset, so you might end up with those in the first release, but probably not. I'm actually thinking to stop that process and just make them creature placeables anyway (ever since I did those gem-holding creature placeable tables a few months back).
Overall, I think that stuff makes great expansion content, especially if many of the additions are similarly themed across a few tilesets.
Basically the only thing these tilesets will release with initially will be the terrain, with more flowers, rocks, and vegetation, and a kit of placeable additional vegetation and matching rocks for thickening up the tile variation. I have no intentions to make bridges or roads for these regions at this time. I do have a few placeables in mind for the badlands, like dragon bones and just lots of randomly placed bone piles of recently slain creatures.
Once I get a basic granite tileset produced, I do intend to fill it with mining variations. Human mines like those from the 1800's, as well as more advanced mine-dwellings like Dwarves would make, will be the goal.