What I do disagree with is your use of the words "broken" and "crippled". To me that implies that intended functionality is not there, or that previously existing functionality is no longer working (correctly). The taskbar has never shown or been visible in metro apps (since metro didn't exist before), so nothing has been broken.
I think is was Anders Hejlsberg that said that a programming language does not get better by taking stuff away, but for people used to using widgets and not keystrokes, broken and crippled will be what their reaction will be.
I would say 80 to 90 percent of 9'ers will be prepared to retrain, but it is the people without IT support that will find it most difficult, even if Windows 8 is successful (which I want it to be), it is not going to be a smooth road getting there.