Minimum and maximum sentences for most crimes were set based upon a much shorter life expectency. As a result the percentage of life a criminal spent behind bars for a crime commited now compared to the time spent behind bars when the legislation was created is much shorter.
The impact of this is that gaol sentences are less of a deterent than they were.
Fo example a person given a 20 year sentence in the past at age 30 may not have expected to get out of gaol. However, a person of equal age given a 20 year sentence now would come out as a fit and kicking 50 year old ( assuming the sentence was actually enforced in full).
I would expect to see all gaol sentences reviewed and the maximum penalty potentially doubled.
Proper sanctions/deterents against crime will reduce the number of offenders. In the long run costs will reduce as the police will not have to arrest and reprosecute as many repeat offenders. It should be combined with a one strike and you're out policing policy.
Goal standards should be set at an absolute minimum to reduce costs including making prisoners sleep in tents rather than nice warm brick prisons.