I mean, I would totally agree that the criminal justice system in our country is fundamentally broken and has been for a very long time.

I think there's a ton of opportunity to totally re-work the criminal justice system within the confines of the current amendments. I think that kind of change would be a lot more politically feasible in the near-term (as in, you could make such changes with 45-55% of the population's acceptance, rather than 65-80%).

The 8th amendment says "you can't be worse than X", but it doesn't put any constraints on how "good" we can make the system. I think the political reality is that we need to improve the system significantly before we can constitutionally constraint ourselves to that new bar.