I used to work with a Russian mechanical engineer named Yakov many years ago at MTS. On the my very first day of work Yakov came off the manufacturing floor where they were assembling for the first time a machine he had designed. He rummaged around and pulled a ball-peen hammer and hacksaw out of his filing cabinet. As he stomped back out to the manufacturing floor I head him mutter under his breath:
"It not fit. It not fit? I show him it fit. I make it fit!"
I think I could just about (have, even) accept any one of the items on that list above. Fixing the Unicode problem in XML 1.0 by erratum is stretching the definition of erratum to the breaking point, but by itself is probably an acceptable compromise. Adding pseudo-QName identifiers to the world is confusing and ugly, but by itself probably not the worst thing that could be done. And allowing XML 1.0 documents to undeclare namespace prefixes, by itself, seems sensible in retrospect.
But all three? Really?
Perhaps, dare I say it, it is time to consider XML 2.0 instead.
I make it fit!
Seriously? I'm not sure what's worse, the tinkering-with-ball-peen-hammers going on with XML 1.0 or the specter of XML 2.0. Are you people trying to make JSON look better and better to me every day?