i maintain that fictional documentaries are a vastly underserved niche now that we have the technology to make really convincing visuals for not that much effort, i mean just look at how popular the latest walking with dinosaurs was!

Doesn't have to be huge, just a few episodes showing the coolest stuff in the setting, like for space Avatar you'd get on Brian Cox to walk through the pandoran jungle and explain the anatomy and ecology that a couple of nerds spent a month coming up with. Like how belter creole was written for the show by a single enthusiastic dude.