I know that headline is unfair clickbait, but there are many things that could be said about this video. Here's a Daily News story.
I think it's interesting primarily to show what can happen when officers fail to gain control of a situation: a mess. A lethal mess. A cop gets shot. Two of the fighting Graver family get shot, one fatally.
Tactically, clearly mistakes were made, but it's hard to second guess. It's rare to find a group that is so willing and able to fight cops. Still, in terms of "things that could have gone better," one place to look is that fight only started after the cops arrived on scene. That could be a place for improvement. Once the brawl is on, well this is why you always want a fight to be two, three, or four police to one. What a mess. What part of "get on the ground" don't they understand.