Let Us Change The Justice System

How about changing the present system with trials by volunteer juries to a system where part of the jury is volunteer, and the other part being a professional jury? Also, how about having more jurors - let's say 30 jurors - and a conviction would require the approval of 27 or more jurors, and an acquittal would require the approval of 27 jurors or more, otherwise it would be considered a hung jury.