I have some ideas to help make this really nice. maybe they been talked about before. but I am willing to kick up some money in the future if these have seriously not been thought of or considered.
-Drawing/shape/pen tools: pens and such for the walls, roads, water/land and general placement of districts. you would 'shape out' the districts and let the generator drop the builds. the walls/castle pen tool would let you draw where you want the wall to gen. out and placement of the castle.
the water/land would allow you to craft a river/landscape that's a touch more interesting. to go through your map.
the generator would still randomize placement of buildings,roads and the like, but it give a bit more ability to create something more to what you're going for instead of hoping the generator makes something close to what you wanted.
I can/could do some illustrations to kinda explain what I mean if need be by 'faking' out a tool screen and stuff. but anyway.
I'll wait to see what the community says on this before going that far.