Hi everyone!
I thought it would be a nice addition to the game if you could set doors to only allow passage for certain dwarves. It could work much like workshop profiles do now, but you could also set access by profession, making it possible only for cooks and brewers to enter your raw food stores for example. This way the whole fortress could be streamlined a little.
Another thing is about moods and artifacts. I had a bowyer create a bow (foreign weapon). I thought what if this dwarf received a special bonus so he could make bows from now on? This could be expanded to all moods. If a dwarf happens to create a foreign artifact, he should be able to manufacture that kind of equipment from then on. A weaponsmith who made an artifact flail once could smith flails from that point, a clothier who made a turban could make turbnas etc. Or, since possessed moods don't give xp maybe they could get this extra instead.
Regarding plants I have the feeling that since the huge explosion of different animal species, the plant life seems quite pale in comparison. I think there could be more variance in where and when a plant can be grown. For example, cave wheat could only be grown on muddied rock but not on sand or clay, rat weed would only grow in hot climates, there could be something that only grows in snow, or only in areas with very low drainage etc. All in all you could never hope to grow everything where you are. Some biome specifications could also be extended to underground plants. Maybe temperature has an effect on them as long as they are above x depth.