Wow... I feel like I am in a minority who enjoyed windows 8. As for the article I disagree with it on many points. I am using this beast for several months (adding the beta releases to the queue) and although I was very sceptic and using the same words with Mr. Nielsen as in the UI is schizophrenic and tries to be two things in one shell BUT you know what? If you are not interested, you don't even see Metro (or whatever its post copyright lawsuit codename is). It doesn't get between your legs, it wasn't always so; my memory did record some awful experiences with CP and RC releases of Windows 8. But the release version is... good, surprisingly. I expect windows 9 will streamline it even more.
I agree that opening two browsers in desktop mode and in tablet mode can be a hassle towards users' memories but hey my workflow makes me using two different browsers in two virtual desktops so I was happy to have this feature without loading a virtual desktop app for windows.
"Lack of multiple windows" um... what? I am running a netbeans, firefox and several consoles running tweaker script programs in ruby at the moment. Of course if he meant the Metro interface, I can't see why do you expect multiple windows on a tablet interface.
And from there I felt like the article goes irrelevant and subjective. I had no problems with flat icons, and to be frank I found the news app the best of the bunch. It does not oversaturate you with the content and is blazing fast. As for live tiles, how can third party developers' choice can be accounted as a failure on Windows 8's usability? I mean if his criticisms were about the Microsoft Apps I would have accepted it but it's saying like "oh iPhone apps icons are too colorful. Shame on you Apple!"
All in all there is a weird tendency of bashing windows 8 in the press. And it doesn't deserve it. It's good, and is trying to change the desktop paradigm whether you like it or not - It is admirable, they are trying to create an original thing but this very originality is hindering them on reviews.
This is my cuppa anyway.