The way it was handled in Reddit was that if someone wanted a particular /r/name, and if its clear that someone was "just squatting" without any content or community, the /r/name is usually given up and given to the new user.
It'd be a manual process at Reddit, but I don't see why that's a problem around here in Lemmy.world? So people can squat on all the names they want, but if they don't do anything with those names and/or abandon their communities, its not really that hard of a decision to give new people the rights to those names.
If the new user is in error for getting control of the /c/community, then the Admins can just undo their actions and give the privileges of moderating back to the original owner/squatter.