On of the most BASIC principles of design in any industry is this: "One shoe does not fit all"
That they are naive enough to think that one interface is going to be able to suit the needs of a mouse and keyboard, a touch screen AND a games controller is absurd. They are completely different forms of hardware interface and as such require very different types of software interface in order to get the most out of them. Asking a mouse user to stop using simple point-click and start using large dragging actions on everything is.... it's beyond any kind of logical thinking. Metro works fine with a controller. It will probably work fine on a touch screen device. But on a PC? Not a chance in hell.
Well I tried out the developer preview, and even the start up screen required you to click and a drag a fullscreen image just so you could enter in your login in details. Then whenever I tried to get into any kind of meaningful apps or system settings from the desktop view, it would keep kicking me back out to the metro UI to adjust the settings there....
Oh, and because the VM I was running it in didn't have internet access, it wasn't able to validate itself as a legitimate product, which meant I couldn't change the desktop display picture. Absolutely fantastic. Because needing the internet to change your display picture is clearly essential...
Vista wouldn't run properly on non-dual core processor PCs that were running WinXP.
Windows 8 will run just fine on Windows 7 PCs.
And device driver issues with Vista won't be the problem with Windows 8.