Great map, I'd love to see a lava/firey styled map on the server, but I do have some points to make:
1. Too much light. Make fire and lava the main sources of light, and use torches instead if glue stone. It just makes the map look a little darker and creepier, mysterious in fact. Make it look dark because its a cave In a mountain but glow stone looks unnatural, like creative-mode built it, but torches make it look a bit more survival like, just a small tweak can have a big impact.
2. Add a little detail and scenery here and there. Some parts of the map look stunning, while others just look like and overuse of cobblestone and stone. Give it more vines, holes, cracks, even parts where lava is flowing out. Give it more detail and make it look like a community that actually lives underground.
Don't take my feedback in a bad way, because this map is great already, but those few adjustments could give the map a whole new (and better) feel and look to it. Good luck, hope it gets on the servers.!