Much of police work requires the guy to be a mostly independent operator, making judgments on behalf of the government/people, and taking what he thinks is appropriate action.

I wouldn't take that away. Instead: tech-up. I'd find better ways to monitor our public guardians, for review by their non-uniformed authorities. Individual policeman-mounted minicams/sound recorders, gps trackers, portable, easily-accessable criminal databases and law libraries for his reference. That kinda stuff.

When a bad one shows up, or a good one has a really bad day, the record will show his mistakes, as well as any aggrevating circumstances.