Quite frankly, we should all be tired of seeing people executed for contempt of cop. Cops will stop shooting people when you take away their guns. Their confrontations and tactics will have to change. I seriously doubt that will ever happen.
But there is no reason why there can't be a federal law or rules of conduct outling a use of force doctrine. Right now there is much left to the interpretation of the officer of the situation. And thus there is little ability to prosecute officers when they pull an Uncle Jimbo. I would expand it to include other rules of conduct beyond just rules of engagement.
First on the list is you can't unholster a gun unless you are ready to fire it. No more intimidations. No more split second bad decisions. If the gun comes out, you must issue a verbal warning and provide adequate time for response. Adequate time would be thoroughly defined by scenarios exploring three categories that represent compliance, active and passive non-compliance.
Second on the list is that a phone call of a complaint by a non-LEO involving a firearm is not justification to draw a weapon on a suspect. The weapon has to be witnessed (audio or visual) by the officer who engages the suspect prior to drawing their own service weapon.
Third on the list is that you can't use explosive or incendiary devices for suspects during non-life threatening pursuits or searches. (IE we need to cut down on the whole tossing flash bangs thing and save it for situations for where someone is in danger.)
Fourth on the list is that no-knock raids shall only be used in searches involving violent crimes. (IE basically never - cops will just have to stake out the place and wait for that marijuana grow op to go get some snacks instead of playing call of duty).
Fifth on the list is that investigators may not willfully masquerade as protestors. There are many lawful reasons for investigators wanting to do this but all of them of recent memory and unclassified interactions of high profile past events inevitably involved infringing on citizen's rights of free speech and their rights to petition their government.
Six - Protocol for non-lethal force & excalation of force.