I'd see it as an admin only tool. You already have a name-uniqueness problem and solution. You can already make a new community with the same babe on a different instance. I.e. there is nothing stopping you making [email protected] when I already am running [email protected]. The proposed tool would allow the admin of the [email protected] to export since stuff from that instance, and presumably the admin of the new community on the new instance could import some of that stuff.

Since follows are driven by the end user, the only practical export data would be old posts. Still, would be useful for community migration.