In Black Panther, during the initial ceremony, Zuri asks whether anybody wants to challenge T'Challa for the throne. He asks each tribe, and then asks the public in general. If anybody wants to challenge, it seems all they'd need to do to rule over Wakanda is to beat T'Challa in an ordinary human duel without any supernatural powers involved.
Later on, this is exactly how Killmonger gets the throne.
Why is it so easy to become a ruler of Wakanda? Why don't they have proper requirements and processes in place so that only the truly worthy can take the throne, where by worthy I mean worthy across numerous aspects (morality, wisdom, strength, intelligence, rationality, mercy, kindness, heritage, etc), as opposed to looking at who's strongest in a regular duel. I mean, by that logic, you'd think Conor McGregor ought to take a shot at ruling Wakanda, because apparently UFC skills is all that matters.
Why have they chosen this bizarre process?