I always thought it would be nice to have a reverse Biboumi to allow people to connect to XMPP MUCs easily from their IRC client. There is a long abandoned project called xmpp-ircd, but according to the author it would require a full rewrite to be really usable.

So maybe we could find someone willing to add XMPP component support to the really excellent Soju IRC bouncer? That would probably be the least effort to get really nice IRCv3 support.