Version 3.8 makes the world editor a little easier to use with some new commands and GUI options that allow you to easily edit the ground tiles so you don't need to manually edit the corners and edges of grass, mud, etc. You can also edit the ground and cliff elevation more smoothly, now.
Mostly I just did it for myself, so I can finish the Panama DLC faster. My goal is to eventually make the world editor as user-friendly as the Starcraft map editor.
I also fixed a bug in which the map corner planes would appear black underwater, and I think I improved performance in the map scripts slightly.