You've got it. I think the basic protocol is easy. Update (or edit) note type. Reverse back to the hash of the original and the clients take it from there.
Could even allow for a "diff" style update or a complete rewrite.
It's coming.
As much as fiatjaf pissed me off rugging me for 5k sats on lntxbot, he's going to make the history books for nostr.