Jeremy Keith lists his various concerns with HTML5 as-is. One prime example that I really hope Hixie will change:
I don’t want to spend the next decade telling authors not to mark up their footers as
footers. It was bad enough telling people not to mark up addresses as
addresses. In any case, authors aren’t going to listen. If they see there’s an element called
footer, they will assume it refers to the device known as a footer, and mark up their content accordingly. At that point, the HTML5 spec will have become a work of fiction instead of documenting what’s actually on the web.