The militarization of law enforcement and its consequences have been a disaster for the human race.
I don't pay nearly enough attention or care about police quality outcomes to comment on whether trends have been a disaster, but critiques of militarization are definitely not something that arose out of BLM. A huge amount was coming from Radley Balko and reason.com over 15 years ago. It was a major libertarian talking point for a long time. As soon as Iraq surplus donation programs started giving free MRAPs and full plate personal armor to police, it was making people uneasy. Early justification for beefing up police armament largely came out of the North Hollywood bank robbery shootout in what? 1998? We didn't want police being outgunned by common criminals, but it's never been clear they need to deal with paramilitary insurgencies that exist in active theaters of combat. Nobody was ever putting IEDs in the streets to blow up squad cars in the United States as far as I can remember.