Have you seen the first generation interface for XBox 360? That one was extremely nice for joysticks, because basically you used left-right to switch between different contexts (game, market place, video, settings) and up-down to choose a specific item. Very fast, very intuitive. But it's not Metro so it had to go.

Unlike a phone, tablet, or computer, navigation of a page is limited to joysticks. Having your nice multi-sized tiles for easy pressing is fine, until you can't press them and end up scrolling in a very confusing way through the page.

You forget about Kinect. You're not supposed to use the old and clunky gamepad any longer. ;)