Wow, Redrobes, that map of Vry's is quite impressive. Something that he used that I believe would be a good guiding principle to help Icos' map is prevailing winds.

You'll notice that on Vry's map it appears that the wind (and hence, snow) blows from the North West to the South East. This results in the north west facing surfaces being covered in snow, and having increased mounds of snow next to them, while the south east sides have less snow and even snowless "shadows" (most noticeable on towers, a boulder in the top left corner, and the structure in the bottom right corner). This seems to help add depth to the map; it could be implemented even while keeping the top-down illumination of Icos' map.

Heavy snow in some areas followed by a sharp contrast of snowless areas (such as on parts of the cliff) would add depth and help convey the feel of a cliff (well, it looks like you are going more for a butte or an acropolis than a cliff proper, but that’s just semantics).

Icosahedron, while of course you should do what works best for you, I'd recommend revisiting the road kink. Roads are sort of like rivers; they tend to take the shortest and easiest route between two places. This does not mean a straight line, but it is very strange for a road to kink for no reason. Of course, you do have a reason; the path leading up to the temple is a direct approach (though that would be a steep incline), sort of like the pyramids at Chichen Itza. But if your software and tools allows it, I'd recommend softer curves; harsh kinks like that are a product of cities, and even then they usually have reasons.