The first thing that crossed my mind reading this was: So UI builders are bad since if they break they form an additional layer between the programmer and the machine? This mindset is exactly what makes application development hard! People working on core elements need to help make good tools possible, and not argue against them. Good tools are essential for a good developer experience.
The second thing that hit me is that XCB is discussed. Is that in any way relevant to developers not working on tool kits nowadays?
Finally I was a bit sad that Qt was dismissed together with Gtk, even though both are hardly comparable. Qt's QML is a really interesting approach and the author did not even know about it... There is no mention at all of clutter in the article, suggesting that all the newer developments in Gtk-land were not covered in the presentation either.
I would have loved to be in that presentation though: I am sure the discussions it triggered were interesting:-)