One thing I've drawn from this that is a bit of a new revelation for me and I think a beneficial outcome of some of even the uglier scenes of violence in the protests is this: Police doing unjust things (and especially using violence unjustly) creates a public safety concern beyond their own limited bad act. That's a pretty constructive disincentive for police to keep in mind moving forward.
If nothing else, don't do bad things because bad things lead to dangerous riots. You can argue about the legitimacy of dangerous riots, but it's clear that that's a possible effect. Whether or not the resulting violent riots are justified is pretty arbitrary.
The cops who would do the bad things are the exact same cops who really want a riot.
Even if that were true (which who knows), the incentives still exist at the societal level. As some one who was finger wagging the violent protests over the last week (while still acknowledging that police action giving rise to it was reprehensible), my view on it has kind of changed, which is a credit to the protests, peaceful or otherwise. You have to kind of divorce yourself from moral judgments on violent responses (which I do think are wrong) and view them as an objective effect of bad policing.
It isn't really enough to say burning a media van (for example) is bad. Of course it's bad. But it's also apparent that a burned police van in KC is one possible result of bad policing (locally and elsewhere). So let's do our best not to have bad policing -- not only because it will result in fewer lives lost as a proximate cause of the bad/unjust policing, but also because it will result in less violence/lives lost as a possible response.
When police do bad things, more bad things (and maybe even worse things) happen. So it becomes very important for police not to do bad things.
In general my views started to shade this way by watching all the videos of the protests and actually seeing how the majority of protesters behave, and then how the cops behave. Most protesters are doing what all protesters ever do, mostly chanting, walking, marching, sign holding, etc. But the cops? How have they reacted? With tear gas, rubber bullets, steam rolling through people both in the protest and bystanders. Like, we're literally watching you all being protested in large part for police brutality and you're literally showing police brutality in response.
So for me (along with seeing that meme about you can't protest like this! not that, no not that, not not that") that really encapsulates the true anger and desire to stop seeing a large amount of the police behave the way they have. And while you shouldn't torch crap, you shouldn't be violent, you're being met violently. It's the only sort of rational way in that situation for it to go. It's truly disheartening, but also truly what would happen in response.