I've been messing around with the map editor, and I have a few minor quibbles.
The deep water looks great on the main map, but looks too dark on the mini map. I would lighten it up a notch or two, so it isn't quite as eyeball wrenching.
Placing swamp next to water puts an annoying sandy beach between them. This isn't how swamps work. The swamp should blend into the water.
You can't create a three (or four) way junction with ridges, it just ends up looking glitchy if you try.
Hills don't blend into mountains at all. I think they could look a little more natural and still be quite obviously hills. The hills are also an odd color and don't mesh well with the open terrain.