nip-5 is only one of the collateral damages of this. Any configuration not supported in more-speech but stored in kind-0 gets nuked if you start the account in more-speech. #[4]'s Damus display_name, too for example.
Discussion
How about a nip that requires user interaction when removing unknown parameters in replaceable kinds? more-speech could load user's kind-0 and not write it if all parameters in the config are in the event.
If not, it could replace its own and understood parameters in the event loaded from relays and upload it, preserving unknown parameters.
