I like how musig is good enough for building federated bridges to blockchains like ethereum. but to add rotation, migration, recovery and more complex signing rules, I always end up with something similar to DID with taproot rules. that would require a new nip introducing those entities and their message validation rules, similar to the signature delegation nip. I'm not fond of genesis events b/c they may go missing as per nostr rules. But I agree that any concept that introduces time as a dimension to identity needs to outsource to a "timechain"