I have commented several times before about making terrains visually different. While trying to thin out mesas in the mapscript, I have gotten more annoyed with the lack of visual difference between mesa and anything else. It is almost impossible to tell from rugged, and very difficult to tell from rock.
I have absolutely no ability to actually create artwork, but I can hack things. I took the peakblend.dds file and turned it into greyscale. Obviously this did not work as-is; there is a black line, and the back side of the mesa did not appear to change. But, I think it looks interesting and it definitely makes the game easier to play.
Could one of the folks with actual art skills make mesa a lot more grey so it stands out? Ideally, the color should appear with altitude so that the grey bare rock stands out above the surface.