Otherwise, good stuff again, Greg.
Boy, that's a lot of screen real estate to cover to close an app.
This will be confusing for people who have to go between systems using W8 and previous versions; say, support techs! It's going to be hard to switch mental gears for the mouse movements between the interfaces; more so than between previous versions of Windows, and maybe more so than between traditional and Ribbon menus in Office.
I still see us sitting out W8 on desktops / laptops. Maybe in W9 the OS and apps will require only one interface, instead switching between Metro and the traditional GUI.