I think I might give adding some of those kind of boulder/rock spire things a try up on the plateau, along with a few scarce patches of grass. If nothing else, those boulder/rock spire things are classic-y enough and grass... well, why not?
And Rufus, the bad cliff parts you pointed out are a style thing - I think they look smoother than using the "proper" tile for it, which instead of tapering off at the end just cuts off at the edge of the tile. I wasn't sure about the water patches though, but I think I'll keep them for now