I'm quite familiar with these arguments. I'm not sure why you'd suppose I wasn't.
The decision of guilt or innocence is delegated to the jury in an attempt to avoid conflicts of interest. Because of the requirement for the judge to be an expert on the law it must be a long term position and so the judge would be an obvious target for bribery or intimidation and will be prone to conflicts of interest when deciding verdicts where the state's interests are opposed to a private citizen's.
First, my claim is that determining matters of fact also requires a kind of expertise. Second, I'm generally skeptical about the extent to which an adversarial system protects judges from conflicts of interests, bribes and intimidation more than an inquisitorial system. Even in adversarial systems judges exercise a lot of control and are bribed and intimidated on a regular basis. Lots of liberal democracies have inquisitorial systems and aren't especially notorious for coerced or biased judges. Is there evidence that civil systems lead to more bribery? Third, this fear of judges siding with "the state" against private citizens can be (and is) remedied by checks and balances elsewhere (like the kind all liberal societies already have) and mechanisms to allow the public to fire judges. Fourth, what conflicts of interest aren't avoidable with oversight in an inquistorial system that are avoidable in a adversarial system?
I don't think a fair, rational system should include anything like jury nullification.
The results are not perfect but understanding why such systems developed as they did is an essential prerequisite to any consideration of possible improvements.
"The results are not perfect" considerably understates the problems, methinks.
Third, this fear of judges siding with "the state" against private citizens can be (and is) remedied by checks and balances elsewhere (like the kind all liberal societies already have) and mechanisms to allow the public to fire judges.
What specific checks and balances do you have in mind? The current system can let serious forensic fraud and gross judicial misconduct continue for a very long time.
In 2004, The United States government executed Cameron Todd Willingham via lethal injection for the crime of murdering his young children by setting fire to his house.
In 2009, David Grann wrote an extended examination of the evidence in the Willingham case for The New Yorker, which has called into question Willingham's guilt. One of the prosecutors in the Willingham case, John Jackson, wrote a response summarizing the evidence from his current perspective. I am not summarizing the evidence here so as to not give the impression of selectively choosing the evidence.
A prior probability estimate for Willingham's guilt (certainly not a close to optimal prior probability) is the probability that a fire resulting in the fatalities of children was intentionally set. The US Fire Administration puts this probability at 13%. The prior probability could be made more accurate by breaking down that 13% of intentionally set fires into different demographic sets, or looking at correlations with other things such as life insurance data.
My question for Less Wrong: Just how innocent is Cameron Todd Willingham? Intuitively, it seems to me that the evidence for Willingham's innocence is of higher magnitude than the evidence for Amanda Knox's innocence. But the prior probability of Willingham being guilty given his children died in a fire in his home is higher than the probability that Amanda Knox committed murder given that a murder occurred in Knox's house.
Challenge question: What does an idealized form of Bayesian Justice look like? I suspect as a start that it would result in a smaller percentage of defendants being found guilty at trial. This article has some examples of the failures to apply Bayesian statistics in existing justice systems.