A great RFC instead a dozen incompatible startups would be the best thing since IRC.
And before you get too down on XMPP, bear in mind that anything that standardizes half-a-dozen chat clients will end up pretty nasty on its own, too. It all looks simple when you're a user of the client, but under the hood chat systems get... "interesting". In the apocryphal Chinese curse sense.
Is there a similar standard for IRC? If not, then IRC is serving a different use case.