I fly around my world with lots of keyboard shortcuts. The hot-corner UI stuff in Windows 8 doesn't really bother me, except for that part where it's hard to hit in a windowed virtual machine... but they provided some new shortcuts like Win+C to get there, or I can run it full screen.
But there's something interesting about this: my parents have a much worse time using Windows 8.x than I do, and the gap is greater than it was in the XP/7 days. And it occurs to me that I use a lot of 'secret' interfaces that are invisible to them.
For them, it's difficult to remember when not presented with something that it's actually still there. This goes back to the 1980s when my dad remarked to me that he didn't like the menus on the Commodore Amiga because he forgot they were there. (You held the right mouse button to show them, moved over them, and then released the button to indicate your selection. It could hurt your finger after a while if you were indecisive.)
After almost 20 years of Windows 95-XP, my mom has a difficult time understanding how to switch among the Start screen, the Desktop, and Modern Apps. I'm pretty sure what would be 'intuitive' to her is for Windows to not get rid of windows. Those changes that Peter Bright complains about at Ars Technica? They're changes that make Windows 8.x less confusing and less alien for people like her. What she really needs next from Redmond is for the Start menu to be a menu on her desktop, and for Modern apps to run in windows... on her desktop.
Mild rant aside, compare this to the state of affairs on touchscreens: there are still some hidden UI features (like swipe down from the top for notifications) but they're not intended to be primary means of interacting with the system. For that, there's the Home button, tapping things on the screen, and swiping from screen to screen (in the same direction that the pager-dots are laid out.) To get into or out of an app, you don't really need to deal with multitasking or the taskbar-vs-modern-switcher (or remember the switcher is even over there).
Once you're in an app, they generally have lots of touchable things. Even the "slide the title to the right to get the menu" convention that has popped up of late generally has a little stacked-bars icon to the left of that very title, to reveal the menu with a mere tap.
Compare this to OS X. I'm pretty sure my parents would also struggle with Spaces due to the lack of omnipresent cues about where they are. They'd leave apps running on other Spaces and forget about them. Then they'd get ultra-confused when clicking a running app in the Dock, which would "activate" it without changing to its space, in which case "nothing would happen" from their perspective. They would not remember the gestures to switch Spaces, and they'd wonder why you would even want to.
Yet if someone like this lands on the Dashboard by accident and still doesn't know how to switch spaces, it provides a little control in the corner to get back to Desktop 1. If you land in a Metro app there is no way to escape except the hidden UI. (Unless you have the recent update and pounce on the title bar fast enough, before it vanishes, which it tends to do during your moment of confusion.) At any rate, the OS X Dashboard provides a nice affordance just for people who don't know the magic, and Windows 8 tends not to.
Microsoft probably thinks that if they throw you in the shark tank, you'll learn to swim with sharks, but they've been backing down because too many people want revenge on whoever is responsible for putting the sharks there.
What's particularly weird about the Windows 8 situation is this: besides skipping a lot of HCI research with their trendy secret corners, how did they not test this? Don't they have a world-famous test lab where people can look through observation mirrors at hapless users trying to use the software? If they ran these tests, didn't they show unmitigated disaster?
My mom's first impression of the Start Screen was, "So where's all my stuff, then?"
That's the real question designers need to be solving. Where is our stuff? How are we supposed to see where you put it?