Some level of community merging seems both inevitable and necessary. Initially, my assumption was that a single instance would be the home for an individual community, but that's just not how things work for many reasons. Communities of the same type should have a way to talk to each other, and more importantly, make it easy for users to follow them wherever they are. The current system is obviously inefficient for many reasons. I think there's a lot of content across communities that is not being surfaced to users for whom that content is relevant, and it is making the entire system feel less lively than it could be.