There should be roughage even at a distance because of shadowing, and points, that's the problem, they are being omitted by the renderer. Even if this was gravel it's definition would be noticeable at this distance, it wouldn't become smooth muddy looking terrain. Especially accentuating their height and shadow in troughs and points in highlight. The colour is also just a surface layer, no displacement to effect FS.
Similar problem with my sand, the sand detail is lost really quick at even a small distance. I had to use a dark low colour just to keep the appearance of displacement at even a small distance.