Pregenrated/Masterkey/HD schemes are not good for several reasons:
- Cannot be used for keys already in use
- Can be used for newly created profiles, but only if created with a supporting client
- If two-level key protection is not done by the user/clients (ie. master key is in client), there is a chance for the master key being compromised, for which case the scheme is ineffective
- Basically works only if the user considers the key compromise risk explicitly upfront, which is not the case for most users.
 nostr:npub180cvv07tjdrrgpa0j7j7tmnyl2yr6yr7l8j4s3evf6u64th6gkwsyjh6w6 's proposed NIP41 scheme is a clever scheme to ease proving the relationship between subsequent keys, but still has the above issues (pr #158, since abandoned).