To give just one example, microdata and RDFa (as well as microformat) contribute to Google search snippets, map location etc.: http://www.google.com/support/webmasters/bin/answer.py?answe...
It would seem to me that decentralized, ad-hoc microformat micro-standards would make more sense than a slow, bureaucratic process. The web will adopt good ideas, useful semantics, etc., so I don't really see the benefit of a 5+ year process of introducing a few new tags.