They're already doing this, generally speaking. The judges are already determining what issues are relevant, either the circumstances of the offence or the circumstances of the offender. They're taking this stuff into account.
It's not done now, and there is no issue. I get that we're now requiring them to at least turn their mind to it, but with the restriction that it has to be relevant for sentencing purposes, I'm not sure. We're trying to solve a problem that doesn't exist right now, as far as I can tell. This would cause more problems than it would solve.