(I want to continue the discussion through VM.)
Well, though, you won't be able to see it in-game, that's okay, but seeing an entire map like that just gives lower ratings because of emptiness. You could've lowed the height, so it wouldn't look empty.
Or, if you wanted it to be like that, make sure to fill in space, because people are rating how the overall map looks, not how it would look like in-game. ;P