Huh? You're not making much sense here. Explain what you mean by a "comprehensive approach".
There are generally-accepted definitions of the word "murder". Go grab a dictionary and you'll find a few.
But there are billions of mitigating circumstances. What specific set of circumstances make an individual guilty of murder, and which make them guilty of man slaughter, and which make them acting in self defense?
There's no historical record of judicial history, and no terms have been agreed upon. Until there's been cases which have tried these events under international law, there's no precedent.
Does Law not work like this in Australia?