We should really start with gameplay rather than visuals. I can't see how any of this makes sense. It's just so hard to make adjustments to a map in this stage. That alone might be why we see so little applicants.
I would suggest a competition to make a gameplay-based layout or alpha-map, and then pick the best of those to let people take a good layout and turn it into a visually interesting map. I don't know how other people would react to creating a gameplay-centric map for a competition in such a visual-oriented community, but I'd go for it myself.