Initially when I started with RWR I had a vision that maps would be eventually primarily made by generating them. Stuff like this
http://www.scriptspot.com/files/u857/gteurotown.jpg was what I was after.
That was one of the reasons the AI was made as adaptive to maps as possible to avoid overburdening map generation with AI related issues. Also RWR map file format is SVG (Inkscape variant) so that one would "only" need to come up with a script that creates an SVG file and add a few additional fields in object descriptions to make use of RWR specific features. I was also hoping back then that real world maps stored as SVG could be possibly used, and maybe they can, but I'm sure there's lots to convert there anyhow.
Too bad there never seemed to be a good slot to experiment with any of this stuff, I find the topic itself very interesting personally.
The tiled approach would be a good middle road with having tiles created by a human to ensure their design make sense and then coming up with procedural ways to combine them. I had an idea of a simplified map editor at some point which would've been operating on the same principles largely, but yah, it would've needed an effort from content creator too to get a decent tile library up.
Another obstacle, online only tho, is that the game doesn't handle sending entire maps and related resource files to joining clients. With some tinkering, a mod downloader-installer could be made that would be started by the game if a server informs from where to download the needed resources. I guess it has quite a bit of overlap with Steamworks, so maybe better to handle it through that.