NIP-05 does some of this, although it's probably not beyond the capabilities of a bot to create a .well-known file at some domain. The solution I have in mind are Nostr identities that it costs money to create, and which can be stored permanently in air-gapped cold storage (e.g. in a bank deposit box). This makes the identity very secure and the user can be confident that they will never forfeit their identity through theft of loss of a private key. Having this sort of identity will hopefully encourage people to invest more effort in building a serious online persona. The idea is that this may organically result in higher-quality "content" created by humans, which then in turn makes it easier and maybe even trivial to separate wheat from chaff. An identity of that sort crucially requires a key revocation and replacement mechanism, which I've implemented at Inkan. As far as prototypes / proofs-of-concept go, I'd say it's been working pretty well so far.