Think about the idea, and not the image itself, because it's obvious that it dosen't fit the art style of the clothmap. But, for example, developers could implement a map in which terrain under fog of war is completely brown, and visible areas have some colour on them, either like in Nezic mockup (preferibly), or with coloured lines as other have suggested.
I am still somewhat against the the idea of the elven map, to a degree. When you are zoomed out, which is what the cloth map will represent, the only info that should be present is critical info. Any additional coloring will compete for attention, it is the way the mind works which makes this an issue. Further more, I think a page should be taken out of Sin's book, which I would be horribly surprized if SD was not already contemplating what I am about to say, to some degree. As you zoom in, priorities for data, as well as the chance for loss of focus on critical information reduces, mainly because there is less information to absorb at a glance. So at levels of zooming in, other things can be brought into focus like coloring land, etc.
Regardless, basic land formation is, in my opinion, Critical information. A means to distinguish terrains with the most impact (i.e. oceans, mountains, and other terrain that may advance/impede movement) is important.
