And why don't we have a better less than lethal gun yet? It's 2016, not 1916.

Perhaps what they need is gun cameras. In other words make a tiny camera that fits on the barrel of a gun like a laser sight and anytime the gun is pulled from their holster it begins taking video of whatever it's aiming at with a very wide angle lens.

This was way overdue. OK, it represents a reduction in the trust placed in all concerned and that is a bad, sad change in society. But the cameras benefit everyone enough that they must be used in more situations.
I've got a fair bit of experience working with people with a cluster of behaviours I call LAMP - lying, accusation, manipulation, paranoia. I've long wished for a continuous recording of what is happening especially in a one on one situation. Ironically, the hidden recordings made by such people have assisted me several times when they were seeking to entrap or accuse me. I have often wished to have a camera on me permanently. More recently I've defused several situations by recording via my phone and making a show of doing it.
More generally, this is going to explode as a technique but I am certain that serious thought must go into how this will change society and how we should manage that. In the absence of sensible people making sensible decisions, things will quickly get silly, bring Orwell's vision closer as our rights are diminished.

The benefit is likely from both sides. An officer is less likely to go too far if he knows his actions can be seen, even if they're not a bad person. It's a stressful job, and I'm sure that in the heat of the moment, they can get carried away. The camera is a reminder to restrain themselves. And the public is more likely to behave in interactions with an officer, if they know that they can't lie also. They can't claim to be a victim if video of them being belligerent/combative is going to end up in court or on the evening news. It's probably also lowering the "filed" complaints more than "verbal" complaints. Someone may be sitting in interrogations, claiming brutality. Before cameras, a complaint would have to be filed regardless of the truth. Now, the police can say, "Oh really? Because here's the video of what went on.", and then the perp just shuts up and no paperwork gets filed. As far as when to save video, they should have a form for people to fill out anytime there is someone involved. Basically, ask people if they want their video saved or not. Of course, anytime there is a physical altercation, it should be saved regardless. Guzmanchinky, the cops do have a less than lethal option, the Taser. Unfortunately, it does nothing against some criminals, due to either size or drugs. And it's not a perfect solution either. Sometimes they have to taze someone that's high as a kite, or is huge and therefore may have a weak heart. They end up dying, even though the officer was trying to save their life, and the y get sued anyway.

Cameras produce a change in police behavior and civilian behavior.When either cross the line of acceptable behavior it is better documented.I don't believe police should individually be able to turn them off. That should be centrally controlled.

Is the drop in complaints because cops were less violent causing less cases for the public to complaint about, or is it because lying assholes could not get away with their bull? That would be the interesting thing to see. The study pointing out that when cops have the ability to turn cameras off it leads to more use of force, makes me think that a big part in the drop of complains when they can't control this, is due to them putting their best foot forward when not being monitored. Power corrupts.
Why should police have the option to turn cameras off? It's not there just for THEIR protection. It's there to protect the public too. There is fault on both sides, and it's better to have more info/data in most cases to try and clear up misunderstandings, lies and corruption. Off course cameras would not help if it involves arresting Donald Trump. Because even if caught on camera doing or saying something, he apparently did not when confronted about it and shown video proof.

Can they make these body cameras tiny, shock resistant and unobtrusive for children to wear to prevent child abuse?

A more accurate headline would have been "Police misconduct and extra-judicial murders plummet when body cameras are worn."

Some pretty thoughtful comments, here.
Chicken or egg? Does the presence of cameras reduce the bad behavior of police or does it reduce the false claims of abuse of authority?
Yes.
The introduction of dashcams a few years ago on Illinois State Police squads led to some interesting results- I saw a video released by the ISP after one of their troopers was accused of roughing up a motorist during a traffic stop. The video showed the cop as being very solicitous and concerned about the well being of the driver (a black man) in question. Once the video was released, the lawsuit was withdrawn without comment.
Win-win!

I found it sadly telling of a system of enforcement in need of major change. I found it sad how the lead-in told us of a massive drop...but never clearly explained what caused that drop. Phooey.