Asslamu Aliakum.
I know Juries are not used in Islamic courts. However which is why I was asking is there anything in the Quran or the Hadith to suggest that the use of Juries is haram? Yet I have not been given any sources to confirm that the use of Juries are not approved of.
The precise description of judge and judicial system in Islam can be found by seeking the apporpriate resources. Not everything is described in full details in quran, otherwise it will be 50,000 pages long and more. You'll need to go explore yourself in order to understand the judicial system details in Islam and what is set and what is not.
The reason Juries are seen as better than Judges because it eliminates the idea of being biased. It is well known that Judges are pro-police and sometimes do not question the evidence that is presented. Juries have a higher chance of looking at all probabilities and with mixed views about the evidence being presented.
Again that is your personal opinion that most learned people disagree with. Juries are better in eliminating bias is mostly a perceived advantage than real, and the advantages at that stop right there with every other comparison becoming a stark failure.
Juries are a slice of the middle of society with inclusion of all intellectual weaknesses (dare I say mediocrity) and prejudices. They carry their own problems, preconceptions, and dare I say racisms and other hatred within their hearts. A judge politically selected in a corrupt society might not be much better, but is a fundamentally flawed approach to apply democratic stupidity on issues of justice. They are also subject to peer pressure, personal sympathies, complexes, or easily impressed with non-substantiated razzle-dazzle debating performance that would never pass a perceptive justice seeking judge. Like I said, juries are easily confused and tampered with and the current system is more of a game where the better lawyer wins, not who has the right.
Juries could consider outcomes that the judge may not have foreseen. It doesn't take a legally qualified person to assess the evidence. Anyone can do this...
Completely opposite! Juries are bound from making conjecture or asking questions and not allowed to consider anything but what was presented. People can lose their rights even if they are clear because a lawyer made a mistake in not mentioning something that even if jury members notice, they will not be able to pursue. As for assessing the evidence, to suggest that a dense group of people are better at analysis than an intellectual superior single person is a statistically proven fallacy. The old adage is very appropriate: "A person is smart, a crowd is stupid"
Anyway, this whole argument is a moot point, because as I explained earlier, juries are not part of the Islamic judicial system nor is there room for their consideration.