Redundancy (multiple instances making communities on the same subject) is a thing that’ll happen. I’m already subbed to communities on several instances dedicated to the same subjects. That can have an advantage, though, in that communities on the same subject but different instances can provide different perspectives on the subject depending on the makeup of the community in each instance (membership, modding, etc). Don’t like the community in one instance? Unsub from that one and hop on over to another one. Having one account able to access multiple instances allows for that. It can also help if one community or instance goes down for whatever reason, there may be another community/instance open where you can keep interacting. So I don’t see the redundancy thing as necessarily a problem.
It’s a start, but hopefully they drop the idea altogether It’s bad enough as it is, we don’t need more.