Hehe =). Maybe I just like the cold parts too much, but at least my first glacier map is rather flat and featureless. So I can't resist suggesting two features. Crevasses, really just being long and thin pits, and meltwater streams, that form especially at the edges of glaciers, and mostly / only in the summer. Water being available, at least very small amounts of it and one season per year, would be fun and realistic and make glacier environments more independent.
Further harder ideas:
Maybe the game could generate meltwater channels inside the glacier. These would begin at crevasses where small streams end up. They would be filled with water in the summer, empty in the winter, providing a nicely hazardous area for exploration.
At least this glacier is completely flat. Would be neat if glaciers were gently sloping domes just like they actually are. And if mountains sometimes came with small, steep glaciers (dunno if this is the case already though!). This would also allow positioning meltwater channels and crevasses (mostly perpendicular to the streams) more realistically.
Also, snow on the glacier's edge should melt in the summer (related to streams), and snow on the high end of a glacier should stay there year-round. This is of course assuming the glacier isn't growing or receding very much. If glacier's edge didn't have snow melt, the glacier would expand.
Maybe the crevasses could be covered with snow in the winter, making natural pit traps? Perfectly realistic, not sure how fun. Could probably use the same mechanic as thin ice on top of a lake / stream.
So please excuse me but I'm a glacier nut and really fond of DF . Thanks for making the greatest game I've played this year.