I am not convinced there has been much positive change since the King beating. We still have the same race-based problems that we have been plagued with for decades. I certainly think that the King incident was an impetus for dialogue on race relations and police reform. It forced Americans to confront the multiple realities of American society. Whites who believed the system to be fair and just were forced to reevaluate.
Many blacks have family members, relatives and friends who have been antagonized by the police.
The King beating confirmed what they already knew. Some constructive things have happened. There have been reforms in terms of police oversight. People have come to realize that policing is too important to be solely the domain of police. With each high-profile case of police brutality, there is a small, incremental step toward police reform.