Different terrain types
My idea is similar with "multi layer" idea but. The idea is: we have 2 pictures for 1 map. First one is ordinary WA map, shopper for example. Second one is kinda "materials" map that should have different colors for different materials. For example yellow means undestructable material, blue is kinda ice, green is sort of glass, that breaks etc.etc. And if there is only 1 map picture, then it defaults to standart WA map.