I would like to have the ability to authorize another password to access very sensitive items, such as re-prompting the master password. In the event that the master password has been compromised and there is potential access to my vault, it would be nice to have something like a second level authorization, to prevent a complete leak of the vault.
Bitwarden already offers a Master Password Reprompt feature that will prevent anybody from seeing, copying, or autofilling passwords (and any other hidden fields) in sensitive items for which you have enabled this extra protection:
Protect Individual Items
Doesn’t directly go to fulfill your request, but if you have some items that are critical beyond just trusting them in your password manager you can use alternative methods such as a password pepper to create a “double-blind” password essentially where your password stored in the password vault is not the full actually used password for the site or service.
That way you at least can feel better about not storing “all your eggs in one basket” if you need.