Going back to the time of King John (a.k.a. Prince John of Robin Hood fame) where his nobles held his toes to the fire to get him to sign off on the Magna Carta, trial by peers and subsequently the right of habeas corpus, etc., has been judged more preferable to legal systems administered by “suitable authorities.” Lawyers are not under oath, witnesses are. Perjury is a felony punishable by imprisonment in most states, and lawyers can be disbarred for unethical behavior, mistrials declared especially when the prosecution withholds evidence, etc. So I think for all its faults, it was decided preferable to have malfunction, let some of the guilty go, etc., rather than lock everyone up for whatever. People are only supposed to be convicted if they appear guilty beyond a reasonable doubt. For whatever shortcomings there are in achieving “justice,” I don’t think it’s the shortcomings of the legal system per se. It’s that certain fraction of humans that will be liars and cheats no matter what political or social or legal system one is under. That’s a fact of life and basic problem about life. Parasitism is a way of life that’s existed amongst many animals and plants eons before some humans found a way to make a living out of it.
P.S. The Magna Carta, etc., did not keep Mary I, Queen of the Scots, Elizabeth I’s half-sister, from being imprisoned for 19 years before she was finally executed. That’s the sort of thing our legal system seeks to prevent when “suitable authorities” are in power to administer “justice.”