I think the video is spot on. A truly intuitive product is one where the basics are understood right away, not through tutorials, reading manuals or other forms of outside help. Those "Charms" are extremely counter-intuitive because you won't be able to figure them out without an explanation. Now if they were used for some extra functionality it wouldn't be such a disaster, but no, currently Microsoft is forcing you to use them in order to access very basic functions like going back to Start or shut down your PC. It's an accessibility disaster waiting to happen even if Microsoft adds tutorials to Windows 8.
The [+] automatically pops up if you drag a window around in Mission Control, you can then drop the window onto the [+] to create a new space for whatever app you're working with.
Then as far as PCs/Tech Gadgets go, I'd say there aren't any "truly intuitive products". There's a learning curve with everything. Do you know how many people I know with iphones, windows phones and androids that don't know how to do certain things on their phones? I showed somebody the other day, when trying to reply to one person in a group text, how to subtract the other names so she didn't reply to everyone. This person didn't have that person in their contacts. But, now she knows.
First time I ever sat down with the ipad (my brother's not mine) I tapped an icon and went into that app. Checked it out for a bit then started looking for a way to go back through the app. Not out of it, just back to a previous page. My brother had to show me as there's no back button. He also had to show me the double-tap on the home button to bring up a list of recent apps. Needless to say, I sat there for a bit trying to get around it. Had the same thing first time I ever tried to use a Mac too. But, once I knew, I knew.
A person who has never used a PC would take some time to figure it out. They don't just grab the mouse and start doing all there is or even the simplest things on a computer. When you purchase a new car, sure you can drive it (I hope) but it takes you time to figure out how to set up certain things. This is the reason the salesperson attempts to walk you through the car's features and functions.
This is the same reason that EVERY electronic device and gadget comes with a manual. If they were as intuitive as some of you say, there would be no need for a manual and the manufacturer could save some money by not writing them. Why pay some technical writer to scribe something that's unnecessary?
Now, ALL that being said, I'm not saying that 8 couldn't do things better (this is a beta and should get better), there's always room for improvement for anything. But, I'm certain Microsoft, as it has in the past, and as other companies/manufacturers do, will have some sort of instructions for its newest operating system.