This is neat. Would it be alright to use some screenshots for a text adventure game?
I think with more features; and more building types etc you could make something worth charging for. This would appeal to those who make text adventure games and wants nice looking city maps, D&D tabletop players who wants whip up something for a homebrew game etc. Writers who want to visualize their cities and towns etc.
Some more suggestions:
1# Export options > PNG, Gif, PDF (maybe last one would be tricky to implement?)
2# Overlay options? More for top down view > Square grid and Hex Grid this could be useful for D&D table top games.
3# Polygon Stickmen like population? Toggled off and On. Some will be still and others moving in groups or/and individually, probably suit a smaller city. Topdown view could just be dots. If Exporting is in and GIF format is one of the options; it would be cool if you had polygon stickmen that you could generate a 15sec gif of them moving about.
4# More zones; like farmland type zones that could have wavey lines and straight line squares as fields.
5# Rivers
6# Walk speed slider or when at street level moving cam around will be at walking speed, unless you hold LShift to make it feel like you are walking around rather than zooming around too fast. A toggle key could switch back to normal cam speed if desired.
7# In light of my initial suggestion of making a commerical product with this to help fund to get in more features, i can see a continent option where one is generated. To save on CPU resources rendering a continent in 3d why not make the continent world map 2d. And then you can place upon it city maps the Toy Town generated in RTS form upon it. This could be a 3d image that is placed on the map, when the user double clicks on this on the world map the 3d town version loads in.
You could have a side panel that pops out with the list of placed towns so you can jump to them- the camera will fly across 2d world map to it and then load it. So in short the world map cannot be walked on or viewed in first person. But the cities made as per normal can. The world map just gives a means to visualise where the cities and towns are in relation to one another.
Also there could be clipart like images that can be placed on the world map (custom import option to) such as icons to depict types of terrain, mountains, forests etc.