I love this generator. It's great and does some amazing things that I think a lot of people trying to create realistic maps want. That being said, I think there are some additional functions that might make this work differently or provide an added use.

Adding a draw tool to the generator runs might help some people.  Being able to eatablish boundaries, or even the shape of the water to draw upon, adds a nice function. I'm thinking this would allow for something like a circular city built around a central point. Or a city shaped around other objects, like a city specifically in the shadow of a mountain, or wrapped around a forest.

Also, offering up a pdf format  export would be nice too so that people might use the image with better definition in photoshop.