Maybe a stint in jail is exactly what they need. Or maybe they need to suffer shame from the people they know and love finding out this terrible truth about them. Who knows.
The confessional has to be confidential or it cannot work...not that it works well all the time but I can't say it any better. It's not at all about who's soul is more important. Who is anyone to judge such a thing.
What exactly are you asking for? Rules that state if a priest hears a confession about certain actions that they must report it to authorities? Will there be a list of offenses available prior to entering the booth? I don't think what you apparently want to happen will actually happen. The guilty just wouldn't go.
On the other hand, a priest may be the only person who could convince a criminal to do the right thing and turn themselves in. This idea that it's some sort of sin shower that absolves one of all manner of evil simply by saying the magic words is incorrect. People can try but it's never worked for me or anyone I know.