I should clarify on how I think this could work:
The reason I say a "randomised dinosaur unlock order" setting rather than digsites is because more species are more tied behind research in this game than the last, so even if the order of the digsite unlocks is randomised, it wouldn't make a difference if the prerequisites and order are the same in research.
Which is why I think if there's any confusion about how this would work, I think it should work like this:
When randomised dinosaurs is enabled in sandbox/challenge settings: the dinosaurs that aren't hybrids are removed from the research menu and are unlocked individually on the digsite map automatically at the random star-rating they are assigned. This doesn't mean all dinosaurs within a specific digsite should become available when the digsite does. So, for example at x stars you may have Tyrannosaurus in Hell Creek but not Triceratops yet.
It would be nice to open up the digsite map at the beginning of a new game not knowing what you're working with. Rather than the same old reliable Nasutoceratops and Ceratosaurus, you see that your options for starting digs are Dryosaurus and Carcharodontosaurus.
It would be refreshing to be put in a scenario where you use species that you don't normally play with at times that you wouldn't usually have access to them. This feature is so important to replayablility that I can't believe it didn't make it over from the first game.