Theorising on alternatives to the contemporary Western legal system have been done for the last century by leftists, and a lot of that gets put into practice on a small scale where it can be. I've been involved in some of it myself. Part of the goal is to prevent creating permanent organisations, such as the police and the court and the prisons, that have a structural incentive to protect themselves against a community trying to hold them accountable.

In fact, note that the concept of a jury is intended to work this way (although is missing many elements, and exists under the permanent organisation of the court) - a temporary organisation gathering to find justice, then dispersing.

Unfortunately it's difficult to tell the exact outcome of implementing any of it on a wider scale, as the times leftism has actually been in power have largely been during times of war where a lot of theory was thrown out the window, or using leftist messaging to implement something closer to a dictatorship. All we know is that a lot of it works when implemented in our own communities.