Right, we are trying to bridge from a user-domain paradigm to a un-domained key-pair paradigm. I don't know if a third way exists and would make for a reasonable and useful bridge.
NIP-05 is really just human readable pseudonym for an npub, by definition. I don't see a way to shorten or make human readable an npub without pseudonymization, so if already pseudonymous, what system would be more intuitive?