"So basically the officer will be able to turn it on when it will help him and turn it off when it doesn't. There needs to be a better system that does not give the decision to record to the officer wearing the camera."
Look, I see where you're coming from but this is a lot more deep than people think. Think about all of those kids/women who are being abused, mutilated, people murdered, raped... with these things being recorded, it leave the door open for files to be leaked, including videos of the above. That means they're also in a position where everything is visible, including your personal information/interaction with the police. Your DL, license plate, car, house, address, anything put in front of the camera is open for hacking and released to the world. There must be a lot of security, policy, etc to go behind all of this. Even then, as we can see these days, things get hacked and leaked.
While this may help a few situations, it may also cause a storm of others.
I think they should pilot this for a while in a few cities and first check for its vulnerabilities and effectiveness before making it mainstream.