If these guys
were changed from an extraterrestrial species into a human subspecies, it would change essentially nothing about the episode. Nothing about the series in general would change.
Really? Because I would wonder “how the fuck did that happen” since supposedly humans from earth hadn’t been there before? If humans have already been through the galaxy and altered the gene pool that actually kinda changes the premise of the entire series. If it were in TNG I’d buy it since much more time and space exploration had past but not in TOS.
It’s not a scenario which would’ve worked in the timeline as-is. Human colonization of space would’ve had to been going on a lot longer than a couple hundred years.