Important to consider privacy around record retention, but I'd love if cops badges were like taxicabs: they are only on duty and supported by the force of law when the light is on and recording is in progress. Ideally, there would be 3+ cameras on the cops body to get a more complete perspective of situations.
Needs systems to limit access to any footage that is not concerning a criminal complaint, but existing cryptographic technology can make it so only the courts have access to the encryption keys if implemented with the right process and key management systems.