Re: mingling of legal principles with faith-principles - I think it makes bad law.
I'm not a Constitutional scholar nor am I a lawyer, but I would have to disagree with you as a Christian. Your way sounds to humanistic. I reject humanistic law that is being taught today. I believe the founders would have too.
The difference between Biblical law and humanistic law is that the Bible does not attempt to save man or usher in a brave new world, or keep the world poverty free or strive for some New Deal society. The purpose of Biblical law is to punish and restrain evil, and to protect life and property, to provide justice for all people. It is not the purpose of the state and it's law to reform man...this is a spiritual matter. Man can only be changed by God's grace and not legislation or edicts by Judges. Humanistic law will never remake man and society. Too much is expected of the law nowadays...it has an impossible burden when its function is no longer to restrain.
Our judges are supposed to be Ministers of Justice with firm beliefs in God. (Romans 13:1-4).
I would argue that the 7th amendment was created for Bible believing Christians. A jury made up of your peers from the community cannot have a lawyer's knowledge of law, but what they can have is Christian's sense of justice and the legal tradition of the community. This amendment is so beautiful because you don't have to have a deep technical understanding of statute law.