Police need to be a part of and work with communities. One of the problems with the Ramboification of the police is that everyone is treated as a criminal. Officers are always looking for evidence of some crime, and can't wait to use whatever new toys they have picked up from the military. This leads to communities not wanting the police around which then leads to more serious crime.

An example situation might be a person who sees some neighbor waving a gun around and generally being pretty dangerous. That person should call the police, but since that person likes to smoke pot every once in awhile they will probably not call the police out of fear that they will end up who one being harassed and treated as a criminal. The police and DAs have made it such that it is in everyone's interest to never speak to the police, and that is how policing fails.

Admittedly not all police officers are like I describe above, but since you'll never know who you will interact with you have to assume they are one of the bad ones. I once had a police officer acquaintance and even he would tell me stories how he would never want to be pulled over by some of the guys he worked with.

Finally, I'm not sure how society comes back from this mistrust. Once trust is broken it is so hard to regain. Body cameras can help, but then you see the above where they are turned off.