Prior to Independence, many people were charged with violating tax laws, brought before American juries, and acquitted by jurors who despised the tax codes. For this reason, King George sought to avoid having such cases tried by American juries.
The ability of jurors to act as a check against unjust and unpopular laws is a big part of the reason the Constitution explicitly guarantees a right to a jury of one's peers. As mere fact-finders, I don't think they're necessarily any better than judges. Indeed, in some types of cases amateur juries are really not very good at fact-finding.
Suppose, for example, a doctor is accused of negligence for failing to perform some particular test. One expert witness says this test was widely recognized as appropriate for people in the plaintiff's condition; another expert witness testifies that because the test would impose some discomfort and hardship to the patient (not to mention expense) it was generally only considered necessary in patients who show some particular symptom which the patient did not exhibit. Both experts may be able to cite medical journals supporting their position; a jury's decision would likely be affected more by the speaking abilities of the witnesses than the actual merits of the case.
Is this that "Living Constitution" I've been hearing about? Look around this thread and you'll find plenty of authority explicitly refuting this.
As mere fact-finders, I don't think they're necessarily any better than judges. Indeed, in some types of cases amateur juries are really not very good at fact-finding.
If a jury screws this up, it's the fault of the lawyer whose side they found against. But when it comes to simply determining whether a person is lying about where he was and what he saw, a jury is the best BS detector you're going to find.