The majority of anti-social behaviour is caused externally through poor socialization and adverse life events. With the advent of modern drug-assisted psychotherapy, criminal reform is becoming much easier after the fact as well (IF THEY BOTHERED TO USE IT).

Punishment should be carried out by having the perpetrator restore damages to the victim. Incarceration should be a last resort for those threatening imminant violence anyways.

The death penalty is essentially a statement that reforming some individuals is impossible, which I don't believe will remain true for long due to coming advances in neuroscience.