How would you feel about having the ability to merge communities across instances?
So let's take this actual example: There's !canada@lemmy.ml and !canada@lemmy.ca. They talk about the same thing, but are treated by the current federation implementation as separate instances.
How would you feel if there was a moderation feature to import another federated instance's community into your own, so that the posts from the other instance automatically show up in the same feed? That way, you only have to subscribe to one community on one instance, but you get content from multiple instances. I'm not talking about crossposting or mirroring/duplicating posts between communities, only displaying the posts from another instance the community's home server federates with, with moderator discretion.
I mean, right now federation is in its infancy so more advanced federation options haven't really been implemented, and this isn't something you want done by default, because two communities focusing on different things might have the same name. For example, "trees" might be referring to cannabis (a joke that originated on Reddit), or a biology community about actual trees.
Makes sense not to do it by default, but I think the option to form a single coherent community across servers is crucial to avoiding platform-killing fragmentation. Otherwise what's even the point of being "federated?" It's just a bunch of separate servers.