It's not against win8 as it is, but what it foreshadows: sure, the desktop is there, but the very architecture of the thing has opened the door for it not being there in win9 if Metro takes off. It's not just a worst-case supposition, every Microsoft dev event is geared towards that direction. They're pushing Office and even the dev tools towards the cloud, the business products like SharePoint are turning towards more app-like models, XNA is unofficially considered dead for game prototyping because it can't run on Metro, they've tried to make the newer Visual Studio Express only able to compile Metro apps (and only went back because devs complained) and so on.
The core of their current message to devs is how easy it is to switch and not look back, and how portable it is: a metro app will run pretty much the same on desktop and mobile, and nobody's missing the obvious underlying message, that the next console will run Metro apps all the same and so you'll get free console-to-PC conversions, no need to port to the Win desktop.
And it *is* a wonderful, very functional thing. I'd switch to Metro any day if it weren't for the closed marketplace, where I can't just put up software for download with a PayPal link, but where I need a MS-approved account, a MS credit check, MS-dictated price range for selling MS-approved software on which MS will perceive a 30% cut. But they've definitely put the framework together for it to happen, all they need to do is switch off the legacy desktop, something they can perfectly do as soon as it's not a commercial danger to them.