This is looking really good so far, Dan. I really like the Asian-inspired mountains.
A few points so far:
--the labels are sometimes very difficult to read, especially where they overlap the mountain linework.
--there's something a bit strange about the mountains on the fire nation's island. I think--if it isn't too late to change this--that it would look better if the highest mountains poked outside the coastline of the island.
--the colour on the sea looks really good, but I wonder if you could also perhaps include an Asian-style pattern overlay? (sort of like
this) I can see that, at this stage, that might be a lot more work, though...
--would you consider mapping the route that Ang took around the world? I think that could be a really nice thing to add (maybe as a companion map to the original)
Also, I've just recently been introduced to the series, and applaud your efforts to redo the map. I myself am working on an Avatar fanart painting, which I hope to complete in a few weeks and submit to DeviantArt.
THW