The biggest problem I see is fragmentation, people are creating the same community in different instaces, /c/Piracy for example. Lemmy should prevent this, community names should be unique, it should have an index of all the Lemmy Fediverse where instances can lookup if a community exists instead of waiting for a user to import that community to his instance. Something similar to what BTC does with the decentralized ledger.
Yeah, we need bots here