1) Police Academy becomes a 2 or 4 year degree, rather than a few weeks/months of training. If you're accepted, you pay no tuition, and get paid a relatively small salary to be a full time student.

2) Federally Operated Independent Prosecutor's office to try all crimes committed by police or politicians (note: I don't know much about the DoJ, so I don't know how much of this infrastructure already exists). This eliminates the conflict of interest between prosecutors and police/politicians that we see all the time. Creates jobs for all the law school grads looking for work, and you can offer student loan forgiveness for anyone who stays with the department for more than 5 years.

3) better cameras. there are some instances where officers have been caught deliberately turning off their cameras before committing brutality, but there are other times where just the jostling of a physical encounter has the potential to accidentally hit the power button and/or stop recording. This seems easily fixable.

Also, I'd put dashboard cameras in squad cars that automatically turn on when the lights/sirens go on, and spot check the videos that are less than 0:30 in length, to catch cops that flick the lights on just to run a red light. First violation is a warning, second is a suspension, third is termination. It's a relatively minor offense, but repeat violations even after a warning and suspension without pay are indicative of believing you're above the law.

4) add on...