NIP-71 once already had replacable video events, but then it was changed to non-replacable events for reasons I can't really understand, so I'm not that optimistic that the pull request you linked will get merged. However there's a page for custom NIPs called nostrhub.io where someone posted two copies of older versions of NIP-71.
Submitting NIPs to the official Nostr Github repo requires them to stay backwards compatible, but then fiatjaf, the very creator of Nostr, makes breaking changes to NIPs destroying backwards compatibility.