Is that so different than how the fediverse currently works? Subscribed content is already being federated across instances I'm just asking it to be organized together. When your instance federates with a community on another instance it doesn't get the entire "5-year" backlog sent to it; only new posts and old content that someone interacts with is sent.

I think there are limits to the scalability of the fediverse, in general, I just don't see how organizing the data differently is breaking anything. Only the most limited servers are going to be impacted from receiving content from three /c/butterflies instead of one. Most people are probably subscribed to the duplicate communities already; I certainly am.