I know this is late, but I must've forgot to reply to your comment, Libby.
At the time, I didn't know or was even aware of the shift mapping technique. Now when I've finally figured it out, I've since gone back and fixed roofs.
I thought the stone stairs were pretty neat, but I decided to change them to the rock ones you mentioned. They fit a lot better with the map actually.
As for the oasis, that is something that good ol' kelarly has inspired me with. I know they're meant for the World Map, but I can also see them as very small ponds, used for decoration.
Thanks for your feedback and sorry for the late reply!