One thing I'd like to see is each tile having it's own temperature, this would require some limited form of air movement modelling.
Space Station 13
http://spacestation13.com/about-2/
was originally created as an atmospheric-air movement test/sim that got out of hand and evolved into a full on game.
I suggest looking at how they did it for inspiration on how to model it here.
Really too bad that one went under. Was looking forward to it because it was quite unique for sure.
That's interesting though about it being an air simulation.
+10
And fyi there is a mod that actually handles it quite well considering there was nothing to work with. Can't remember the name off hand but it's there none the less. May also help him out.