I forced myself to watch the entire video and those were minutes I'll sorely regret wasting.
A couple of egregious points: Windows 8 tells you about the corners the first time you run it. Actually, it doesn't just tell you, it shows you. The concept that "placing the mouse in a corner does stuff" is so basic that claiming it's hard to discover is just disingenuous.
The second point is about touch gestures on the touch pad. Actually he has a point, it's a bad, bad experience, bad design, bad implementation. But that's not a problem with Windows, it's the silly touch pad driver that's doing that. Déjà vu, anyone?
My anecdotical experience: I have a laptop with an OEM Synaptics touchpad. When I upgraded it to Windows 8, it kept working exactly like it did before.
It wasn't perfect though, as scrolling didn't seem to work in Reader, so I went and tried downloading the newest driver from Synaptics. Windows 8 wasn't happy (it immediately listed the old driver as an important update) and neither was I as the charms bar kept appearing. Not nearly as disruptive as the task switching, but still quite annoying.
Fixing it boiled down to disabling "Edge swipes" in the control panel; to Synaptics' credit, very little guesswork was required as their control panel, while horrible to look at, comes with short videos showing what each option does. All in all it must have taken me a couple of minutes, tops.
Ok, my mother probably couldn't have figured it out by herself, but again, it's a problem with the laptop manufacturer. If anything, it highlights why it was a good idea for Microsoft to start designing reference hardware or, at least, raise the bar for certification.