One need only look at all of the crimes that are committed by repeat offenders who never should have been let out.
Or look at the people who have remained in prison even though their innocence has been proven. Then we have plea bargaining. If you are arrested for a crime then that is what you should be tried for. You shouldn't be allowed to cop to a lesser crime for a shorter sentence.
The problems don't come so much from our laws as they do from our courts. We let lawyers pick juries, why? If we are going to have the jury system the shouldn't it be the first 12 people. But it never is. First it tends to be the people who couldn't get out of jury duty. Then each side gets to cherry pick a jury with endless questionnaires and studies.
Another problem, especially in civil law, is that jurors are, more often than not, completely ignorant of the subject involved. Is a retired secretary competent to judge whether a product is at fault if it fails due to improper use or has been altered in some way? How about a student or a grocery clerk? Unless you have some engineering knowledge it is hard to tell.
Look at the famous Ford Pinto case. A 1 ton van fully loaded slammed into the back of a stopped Pinto at 80 mph. The Pinto caught fire and Ford was blamed for the death of the people in the Pinto.
But the Pinto was completely demolished and coroners said that they all died instantly from the impact, not the fire. Further Pintos weren't really any more prone to fires than any other similar size car under those conditions. But juries feel sorry for injured parties and award millions.
Given the costs of trials and what is at stake we would be better served by a professional jury system. Or at least one that pays people enough for their service and enlists people who have an understanding of how things work. A system that doesn't let anyone skip without a reason.
There are plenty of retired people from every walk of life who would be willing to serve and are more competent.