Some natural terrain improvements, like Crystal Crag, sometimes look odd -- they seem to be out of place, kinda attached to the ground. I think it's because their color doesn't match the tile's color they're located on; they're "made" of too distinctive material and there's no smooth transition between them and terrain. It would be nice if there were a few versions of (at least some) terrain improvements so they would match multiple surroundings. The FE world would look way more natural and attractive.
It's also true of some non-natural terrain improvements. But it's not so unsightly since every building is naturally out of place in the wild Still it would be nice to see some sand on outposts placed on desert, etc. In Warcraft II every building, AFAIR, had three versions: grassland, snow and desert. I know that 2D sprites are much easier to make and alter, but modern 3D games should look like just as nice as old 2D games. At least I want FE to look beautiful