I don't think it's even a matter of having the balls to drop the desktop in Windows 9. I think that it'll always need to be an option, even if there's an explosion of Metro apps over the next few years. People will continue to need things like AutoCAD, or Premiere, or even business software like Microsoft's own Dynamics offerings. Now, there might be a valid question about whether it's there or not in a consumer product, but for professionals, I feel like there always will be a version that includes a desktop. I know that for myself, I'll almost definitely always continue to use the version that contains a desktop.
I think part of the confusion is that people don't really know the difference between Windows 8 and Windows RT at this juncture. On an ARM-based device running Windows RT, yes, everything will be locked down. On the actual x86 (or x64) Windows 8, you're free to use the computer the same way you always have. It's just that if you only use Metro apps, those will only be available from the Windows Store. Steam will still work perfectly.
As for me personally, I couldn't care less about other people's opinions about Windows 8, whether it's Gabe Newell, Notch, or the President's for that matter. I ran Windows 8 dual-boot for the Developer Preview and mostly stayed in Windows 7, because it wasn't ready. With the Consumer Preview, I kept dual-boot, but it mostly became my daily driver. Now with the Release Preview, it's the only OS I have installed.
To be honest, it's exactly what I want in an operating system, and the Surface Pro, at initial inspection from the presentation, appears to be exactly what I want for the form factor. For me personally, I love that I will be able to have only one device which I can use on the go as a simple touchscreen tablet similar to the iPad, and when I'm at home or at the office I can plug in a keyboard and mouse and have full access to all the functionality I need in those situations. I've got a separate tablet and laptop, and because there's things that the tablet can't do, at the moment I have to make a conscious decision of which one I'll need before I travel somewhere. With something like the Surface Pro, I don't have to decide. And the fact that I can still run my hundreds of Steam games is just the icing on the cake. In fact, I've heard the majority of complaints coming (not from here, but in general) about using Metro on a large monitor. Personally, I've even had zero issues with that on a 23" 1080p display. If you don't like the hot corners, there's still the Start button on your keyboard, despite it being gone from the taskbar. And since you can still pin any programs to the taskbar as well, I think people are sort of overreacting. But, if they don't like it, that's their prerogative. It just doesn't affect the fact that it's pretty much exactly what I want.*
*The preview Metro apps still need a lot of work though, I hope the RTM versions are better.