It looks like at least one Illinois judge has found fault with the recently enacted state law that permits 6-person civil juries. According to Cook County Associate Judge William Gomolinski, who found the law unconstitutional, it takes a constitutional amendment, not a law passed by the Illinois General Assembly, to reduce the number of jurors from 12 to 6. In his opinion (Kakos v. Butler), Judge Gomolinski does a good job of not only discussing the history of a 12-person jury in Illinois, but also the benefits in comparison to a 6-person jury.
National Law Review: Amendment Reducing Size of Illinois Juries Declared Unconstitutional