I must be failing really hard at communication here. I keep trying to say that I think it'd be better if we, the authors, didn't know all the facts. Because the more facts we nail down, the less mysterious the setting will seem from our point of view.

I am also trying to say that allowing multiple, independent origins for isolated groups of the same species would be a good thing. Because then someone could, for example, write up a kingdom of people that were transformed from bees into humans a long time ago. Something like that would not be allowed if we'd already decided (for example) that all humans came to the planet through a dimensional wormhole.