Since this thread is also about technological progress, I think I might as well kick off a discussion on that. I remember the devs saying that eventually we should be able to play in earlier ages. If that is true, isn't it a little silly that a third generation dwarf would know how to make a catapult, metal weapons, ect? Technological progress should be a gradual thing, with dwarves and other civilizations starting out with the basics and learning from there. Some civilizations are obviously more likely to be adept to technological progress than others (With Elves and Kobolds barely learning anything new in that regard. Though perhaps they might just have different technological progress trees) as well.
How would discoveries be made? Well, for basic discoveries, dwarves might just learn them from trial and error and experimentation. An apprentice might make an accident that turns out to be a great discovery, or a dwarf might see something in the natural world that inspires them. Later on, as writing systems develop, there might be more formal institutions dedicated to research and discovery. I think this opens up a lot of avenues for fun. It might be cool to generate a world at its 5th year, make some cool technological discoveries as a civilization, then abandon the fortress and speed up time to the year 200 or so and see how those discoveries affected the world. Perhaps even the names of great inventors might be engraved all over the walls and might be commonly discussed among academics.
Another fun idea with technological progress are dead end scientific theories. Not everything works out after all. A dwarf might even go mad trying to make his crazy invention work even though it is an impossibility. Or there might be some crazy discoveries that do work on some randomly generated worlds and not others, for some of the more fantasyish contraptions (In one world, portals might be feasable technology. In another world, they might not).