Looking at the Linked Instances, most instances have at most a few hundred instances linked. What happens when there are thousands, or possibly even millions? Could too many instances require significantly more powerful hardware, or even be impossible altogether?
Generally I think duplication isn’t great because it means people subscribe to all of them and cross-post in all of them. A lot of client apps don’t deal with this well, yet.
I mean just have a community for cats on instance 1 and a community for dogs on instance 2.