Remember that movie with Robert Duvall and John Travolta, called 'A Civil Action'. I like this quote from it.
"This stopped being about justice, as soon as it entered a court of law."
Very true. The sytem is setup in a way that the courtroom gives you a SHOT at justice. It does not guarantee it. Professional juries would be susceptible to bribes, the same as judges and district attorneys are. I like the current system of unique juries our our "peers". It's not a perfect system, by a long stretch, however. I wouldn't mind some required classes in high school that would try to prepare our citizens to be better/impartial jurors. I don't see it happening, though.