This is the kind of behavior that I expect to see widely across America if we rely on random citizens to patrol instead of police. He was told by 911 to stay in his car, but instead he got out and shot Treyvon in supposed "self defense".
Police in the US are professionally credentialed faster than a master plumber. After less training, less testing, and less oversight, they're handed lethal discretion and informal qualified immunity latitude, in less time than it takes for someone to hang a shingle out as a one-man plumbing business.
The same solutions will not be applied universally across the US because the challenges are very different for different communities. Many Black communities that are asking for community policing will benefit; doing community policing in white spaces is not guaranteed to make them any safer for Black people, but I don't know if that's being called for. And honesty I'm not sure it makes them less safe, either, when you look at what happened to Treyvom Martin and Ahmed Aubrey's cases (and all the others that do not get media attention).
The wikipedia article says that he was injured and that he got into a conflict with him before shooting. He claims that this was while he was returning to his car and he was attacked by him. If this is true I see no misconduct by him.