Hah, though I love Warhammer 40,000, I generally don't like sci-fi dark-ages. I am starting to think that I may be false, but I think so far from what I understand, that the factions in Starsector still, at least, have the ability to produce things of their own. They may not be innovating, but they can still build new things. Whereas, in WH40k, the Imperium can't actually build anything, and relies on vehicles referred to as artifacts.
I dislike it because the Imperium controls huge metropolises and yet no one, not even the tech priests of Mars can figure out how to, I dunno, build a NEW tank.
But that's just me!
I used to want to design a game, but I just don't have the patience to program, and I am absolutely not artistic (though, I wish I were!). I like how you say that in Starsector you can more easily see results for your work, but even still I don't really know what I'd /do/ with my limited skillz!