Currently, a map is seen as a collage of yellow rectangles (the submaps), all labeled with a more or less descriptive text.
I suggest that someone who generates a submap can save a thumbnail of it's ingame looks (or a crayon drawing...) to the same folder.
This would not 100 % represent the exact submap because obviously, that is chosen at random when a battle map is generated.
It would, however, show a generic overview of the level because something barn-like would be some kind of barn, a N-S road would be some kind of N-S road...
No true WYSIWYG editor but a huge step towards user-friendliness because you could "see" how the level fits together.