Why not make the rule: "at least one of 80/6667, and at least one of
443/5222".
Also sounds good to me. I opted for the smallest possible change
(6667->5222) but what you're suggesting lgtm.
I am also concerned about the choice of XMMP "because the XMPP protocol
is slowly gaining popularity within the
communities on the internet".
Shouldn't we focus on secure protocols that are widely used right now?
Alternately, we could add other widely used SSL ports in addition to
XMMP, and perhaps increase the rule to "at least two SSL ports".
Imho the challenge is in finding port number(s) that accurately reflect
what Tor is for, while also having a sufficiently large user base for it
to be relevant. XMPP probably has more users than IRC, and is a good
match for what I think Tor would consider important (communication).
Also note that we now have Tor Messenger. Other protocols (SSH, IMAP,
POP3, SMTP) are indeed more popular but I feel that those less reflect
the goals of the project, and they are certainly abused more.