I have my stacks of flametal on a friends server waiting.

I think there should be dragons that breath fire. I think (as a previous poster stated) there should be pools and/or rivers of lava, or even volcanoes. You'll probably need fire resistance just to visit (similar to mountains and cold).

Building with ordinary wood will likely fail, You'll need stone based structures.

Fires will burn out faster , if even a possibility, etc etc.