What do the protesters want? I’d suggest some distinctions.
It may be that much of the protest is not about achieving any specific reform, but simply to express outrage at the way (too many, it is alleged) police behave. It’s not that the police don’t have the right rules and regulations — it’s that they don’t follow them. Fair enough, though of course the allegation need not be accepted.
And there may be some specific reforms that may make sense and are needed or can at least be discussed, depending on the city. NRO has had pieces suggesting that police unions need to be reformed; maybe some cities do need to have stricter rules about the use of some kinds of force in arrests; maybe some places need to have a better way for communities to interact with the police; libertarians will assert that there are too many laws about drugs; etc.
But some of the specific reforms will be simply bad. Ending capitalism, for example, or racial quotas for hiring policemen, or not arresting people for crimes that really ought to be crimes.
And, finally, some of the protest is not about anything, really, or is just misdirected frustration blaming the police for the community’s own problems, to say nothing of the rioting that is just an excuse for committing crime.