I like the idea. A burned npub is like a lost npub. Compromiser can burn it. Fine, as long as there cannot be a migration event together with the deletion. I don‘t see a solution for migrations in nostr because time is not absolute. Referencing other events can only give relative time.
I've submitted a patch to the event deletion NIP (09.md), adding the possibility to burn or retire an npub, rather than merely emptying it of events through deletion.
You can see the proposal and comment on it by opening the note below or by clicking https://gitworkshop.dev/repo/nips/proposal/23791a60b65c898b2eaa500323ef918e0c9d61b6a6dc16d7da42a3cc935075d7
Discussion
They were discussing (in a separate dev hellthread) that we could add a layer of validation to a migration by using WoT and NIP-05, or even a linked key.
Hyperlink, in case that doesn't render well: