Similar, but somewhat unrelated: there's obviously no delete feature, and even if there was some relays would probably just disregard. But what about an event that signals to relays "this is a replacement event" such that a client could build a UX around showing the edited / newer version of said event, but in the details show the ancestry / prior related events? That way clients and relays that want to support editing can, while others can continue with the "all tweets are final" approach. I highly doubt I'm the first to suggest, but didn't know where to look.