A feature I would like (I think its planned anyway) is the revamp of the workshops. I would like them to be designated rooms with furniture in them, working like the hospital, including its internal supply storage.
I'd have to see how hospitals work after the supply interface is made more intuitive or self-explanatory and the bugs that cause hospitals to become black holes for hospital-useable materials are fixed to know whether this would actually be a good thing...
Re. dwarves in space: While dwarves would doubtless be the first race to develop the rockets necessary for space travel, I imagine that being without an atmosphere and exposed to the rays of the sun with no earth under their feet is something like being outdoors... multiplied by a bajillion and two. If you have a science fiction (or fantasy in space) setting with fantasy races, this would be a great reason for people to have to return to the mother planet every few decades/centuries/millenia to get the latest dwarven technology that the dwarves refuse to bring to the stars themselves because, as they say, who with sufficient intelligence to invent anything wants to get closer to the stars and further from the earth anyway. So whoever controls the mother planet or lives closest to it has all the best tech, assuming they don't do anything to piss off the dwarves (although we know that in DF that's "basically anything but be useful to them")... at which point the dwarves might very well end up owning the mother planet? Well, it could get interesting one way or another, much more so than simply having dwarves out in space where they don't exactly belong.
Then again, DF dwarves would probably see the terrors of space as some sort of challenge, so... who knows.