I love the way that the various elemental, mythical and natural creatures get real distinct morphologies now.
*The following text is more a wishlist that continues this trend of more detailed simulation*
Hopefully the same will happen to plants and trees eventually: self seeding and creating natural copses.
(as well as imported plants escaping from fields and propagating if environment suffices)
creating a more dynamic flora scene than the now totally random scattering of subset-X plants/saplings.
will probably not happen untill "multi-tile trees" ect.
various new and rare ecologies (plant/creature sets) that no dwarf has ever seen, special ecologies for special subterranian hounts have been hinted at in any case.
(There must be stuff for the fauna to eat, unless they are magical manifestations offcourse, but that only holds true for say magmamen etc, not so much for batman or antpeople.)
additional semi-randomised plants/creatures might be cool.
Natural e-cologies are a pet favorite of mine.
[/biosci]
Another suggestion that has little influence on gameplay:
(unless you count adventurers trying to walk off the map)
is the option to create worlds rather than 'quilt' regions that look like a part of a larger world, but act as a pocket universe.
I personally think 'civilization'(r) handled mapping a sphere to a rectangle quite adequately by using a toroid. (the mapgenerator scripts were pretty nifty too, though obviously less intricate than DF)
I'd love to hand-draw a map of a consistent world or seperate continents thereon.
[/cartophile mode]
-derailed much yet? :p