I think community consolidation/aggregation is something that might want to be looked at. It’s possible to have a gardening community on multiple servers with different content. This will confuse people. So having a way to merge posts from two communities into a bigger community per server may be a good idea. So if you set up gardening communities on two servers you can choose to have posts show for each of them in your community. And making this a server or community setting still gives the ability to either have this or not have this if the communities are truly supposed to be separate. This would also give some kind of redundancy where the original community server can go offline but multiple different servers can still exchange messages that eventually make it back to the main community. Truly decentralized.
The way I was thinking you could still go to the original community and skip the aggregated one. So you could have c/gardening and c/flowers, but also c/backyard which could combine the two. You could still go to either one, but for easier discoverability you could create aggregators or include an aggregator in your community, and do this cross server. So if you have two very popular and overlapping communities you could combine them easier. Could also be a client feature I suppose. But right now you’d have to manually hunt for the possibly dispersed communities yourself. Alternatively I guess there is an argument for smaller communities being better which I do agree with. It was just a not very thought through idea :) Or you could have community redirects. So c/technology on lemmy.world could decide to seamlessly redirect to c/technology on Lemmy.ml if wanted. Edit: although the more I think about this the more it sounds like more trouble than it’s worth.