@sun I guess nobody thinking this would be a great idea has read lain's article about it from years ago.

As for the objection: The resulting design will very likely not be compatible with multiple AP implementations and dealing with keys/trusting them will be broken (like XMPP) or overlooked and broken (Matrix). Due to the nature of Fedi DMs, you are essentially dealing with groupchats. The final product will be OMEMO, but instead of XML as the base protocol, JSON will be used.