I'm not sure if this has been suggested before, but at least I've found nothing in the search function.
Something that occured to me while playing with th map editor yesterday was that it would be very useful (though probably hard to implement ) if one could overlay/scale a jpg image in the map editor, maybe at 50% opacity. It would make creating maps based on "real" data - world maps, or, in my case, a map of Magnamund - a lot easier and would save having to print out maps with a raster overlay on it.
Yeah, I'm lazy.
I know that map editor patching is probably not very high on the list of priorities right now, but I thought I'd throw it out there.