Oh, improvements? I have very few ideas, and they are largely ones that other people have been saying for a long time.

But, much like improving a technology, you need metrics and you need to decide what your goal is. Presumably society will want a balance between everything listed, not just one...but what are the terms of that balance? As it is, every lawyer, judge, jury member, voter, journalist, and prison warden are all winging it, so we aren't getting a balance, we're getting a mish-mash result from this tug of war. (I wonder how much of that comes from the trial process being adversarial - the assumption is the truth survives if both sides push in opposite directions as hard as they can. Leaving aside if that works as intended, sentences and guidelines are likely heavily influenced by those for whom that environment is familiar and accepted. That's a digression though)

Anyway, if we don't know what we are trying for, how can we take steps towards it?

But to give some concrete ideas:

* Improve mental health care, in prison, but mostly out of it. My understanding is that when there was a big push to close "asylums" a few decades ago, significant groups of those populations (and those since that would have gone there) quickly moved to prisons. And even if that was unrelated, it's not hard to find that prisons hold a lot of people with mental issues.

* Improve the social safety net - if people can feed themselves, their kids, and live where there are jobs (or at least opportunities) it becomes much easier to say that there is no need for crime. I think this will become a bigger deal - automation may be costing jobs, or may just result in shifting them, but either way unskilled labor that pays enough to live on is definitely shrinking. I'm very curious about basic income, but the potential for unforeseen side effects is huge, so I'm cautious.

* Non-violent offenders don't need prison (nor lesser violent offenses and/or those that aren't likely to reoffend - a high school fight is different than a murder). Give them GPS trackers, force them to stay inside, to attend whatever sessions are needed. This might be honest real help, or it may be boring them to tears with a shrink or group meetings, depending on your views, but that means it's either Rehabilitation or Punishment. :) But it keeps people in contact with real society (in particular it maintains their corner of society: Friends, family, news), doesn't create a separate concentration to train people to be harder criminals, and is cheaper to boot! Critics would say this lets people stay home and watch TV all day, which is valid, but if Punishment is the goal, there will be downsides, the degree to which can be negotiated.

* Better work plans. I can only imagine getting a job as an ex-con is hell, based on how every job application I've ever filled out asked about it. This ties in with the safety social net above - better handling of managing jobs for everyone, but in particular ex-cons. If you have more to lose, it's easier to stay in the lines. (This is probably the hardest thing in this list to do, because it is to want, hard to figure out how)

* Give white-collar crime the same sentences. If every one of these wealthy execs and financiers that "settle but admit no wrongdoing" got the same treatment as the poor black 20-year old that robbed a 7-11, I'm guessing there'd be a bigger push for reform. That's not just cynicism - I'm guessing most people, including myself, don't realize how bad it truly can be, and thus have only vague interest in improving it.

* End prison rape. It happens. Not rarely. We know it happens. and we joke about it. Not rarely. I know very little about trauma, but I do know that someone that has trauma can form some very hard opinions very quickly. And if most people make jokes rather than care about your trauma, and have no/limited support network, and have no/limited mental health care, I can guess in which direction those hard opinions are more likely to go.

I'm probably missing some, but these are the ideas I've seen that sound to me like they're going in a sensible direction.