Issues in Criminal Justice break down into several related but distinct categories.
First, the number of people killed by police each year is statistically higher then all comparable countries. A few of those killings are very questionable and disproportionately, but not exclusively, affect people with dark colored skin. A large chunk involve people with severe mental issues who may or may not have been misunderstood by, or misunderstood, officers involved in the shooting. The remainder were clearly a threat to the officers or the public. It would be really good to reduce the number of people in all three groups but particularly the first two.
Second, we have extensive evidence of biasness towards people with dark skin. I have seen the opposite. I worked in an area of DC with a heavily African-American population. When I went to the local grocery store, I was thanked and invited back with a smile by the security people who universally had much more skin pigmentation than me. The same security people would glare at and check the bags of pretty much everyone else in the store. I was profiled. Every time. This needs a great deal of attention.
Third but related, the courts need to be held to the 14th Amendment - the one with the "Equal Protection Clause". Penalties need to be reviewed as a matter of course and anything outside the norm needs to be explained or brought to the norm. It that means harsher sentencing for light-colored people to average things out, maybe the harsh sentences for non-violent crimes will get a faster review.
Fourth, the "War on Drugs" needs to be updated to the "War on Drug Addiction". All the money we spend keeping people with drug problems in jail could be more efficiently spent on preventing and resolving drug dependencies - unless the real goal is to keep potentially liberal voters from voting. A quick way to discourage drug incarceration would be for someone to challenge the permanent removal of voting rights after a person completes the mandated punishment for a crime. If reintroduction and a second chance are truly goals of criminal justice, a citizen should be able to vote after paying their debt to society.
Fifth, the militarization of police needs to be scaled back. In some cases, a gang may be heavily armed and require a severe and dominate response from police. However, those are very rare. Police would be much better at preventing the establishment of the gangs in the first place by being more involved with the societies they are policing. This will require a large increase in the number of police and major investment in community outreach counselors.
Sixth, although I never thought I'd be spelling it out, the police should not be summoned by a private company to use excessive and potentially deadly force to end a demonstration!