I could only play for a few minutes as my daughter woke up soon after I started, but from what I can see it is really hard to get started, and with the bedrock layer much higher than normal there is much less room to build. Eventually everything will burn except the brick and bedrock which leads me to believe that this is a kind of experiment like this: http://i.imgur.com/QO4B1.png
I loved it though. If everything except brick burns eventually, then I can see it getting crazy. Fast. The only way to make it work is if EVERYONE works together and starts right away at building cobble generators and working to build halfsteps, and putting bricks in the sky to make a shadow of safe area for grass to grow which would allow for non-hostile mobs to spawn. I'd like to see the whole server cooperate like that :-)