I argue HW isn't needed at all.
That sort of organization doesn't scale. It's much better to develop tools and allow individual communities and their mods/curators to collaborate and figure out ways to mitigate things within their own boundaries and in their own terms. It's insanity to expect Hivewatchers to be judge, jury, and executioner for every community across the chain.
EXACTLY! Each community has the ability to mute/ban users who are misbehaving in their community.