Many users run a permanent IRC connection with a bouncer or just run irssi/weechat in screen/tmux on a server. There may be occasional reconnects for them due t

Many users run a permanent IRC connection with a bouncer or just run irssi/weechat in screen/tmux on a server. There may be occasional reconnects for them due to netsplits etc. Usually they also configure their bouncer/client to automatically authenticate when they connect. Using any sort of authentication involving a separate channel would stop them from authenticating without user interaction. Unless of course it could also be automated. However, I doubt it is easy enough to create a standard for this. If your only goal is to stop leaking the password in cleartext, that could also be achieved using established standards such as SASL or a challenge-response mechanism such as CRAM-MD5.