There is still a whole bag of philosophical problems to be solved regarding punishment. Do you punish to prevent the same person from doing something again, do you punish as retribution for the victims (then it doesnt make sense to tax those to provide prisons), or do you want to set a sign against others for not doing crime. Atm there are many inconsistent terms put on various charges, which merit resolving. I read a few times that the legal system works because most people are aware of punishment, not because it punishes most punishworthy deeds, or because its particularly fair. In that case a bayesian system might have very little practical difference from the current (except for all those not guilty). A decent reform would include some liability for attorneys to withhold evidence, or threaten the accused and such. Maybe someone will put up a whole thought out concept.