My Windows Phone navigation idea (UX tweak)

I've been playing with Windows Phone 8 for a while now and I love both the simplicity and the design. But as usual, I felt there's room for improvement so I did my own take on a vertically tabbed interface. I know it takes a bit of the horizontal real-estate but I think in this case it's justified. Also the screen sizes on most windows phones are pretty wide anyway.

Windows Phone UI / UX navigation mockup (via hype4media)