One look at it:
http://www.aptaracorp.com/assets/res...QAMay_2011.pdf
Perhaps "Classic EPUB" will drive "New EPUB" off the bookstore shelves?
Or, the next Internet Geek Hero will be the guy that provides the tool to de-fang EPUB3.
(If they stick to XML, it won't take long to find a point of attack.)
Luck;
Ken