I recently had a bad experience due to a UI mistake on ENS.domains website. Long story short my domain is locked. It won't reset until expiration, not even during grace period, but after i totally lose ownership and goes to public hunting. It makes good sense to have a backdoor for cases like mine. In the link you will find more details of what happened and my proposed solutions. Some may be more technically difficult others are easier.
Generally speaking the straight forward solution I am proposing is to change the code that controls the temporary premium period to add a 10 days before the premium applies in which 10 days ONLY the last owner of the domain can grab it. This way, the domain resets fuses, the owner regains access without losing his property.
As an added security I would request to change the "extension" function. Let owners of locked (or all) domains to allow/disallow third parties from extending. Disallowing would mean ONLY owner/manager of top or sub domains can extend the top domain. No need for mapping of ownerships. When extensions from public is set to off then when request for extensions is sent you look if the address owns that domain or subdomain by parsing their assets i suppose.
More suggestions for even greater protection of wider range of use cases are given in my post in the link...