This Concept looks really like a step forward from what Windows 8 and all the desktop apps look right now. I hope this is where Microsoft goes for. Maybe they need to create a design guide like this one for developers, and if developers all follow up updating their interfaces, Windows would look more complete. The layout is very open and the big buttons make it touchable
I have an idea for fixing those WMP controls: redraw the actual buttons with shapes (I noticed you just copied them from a screenshot,) set the fill to 0% and add a white stroke. For the button icons, redraw them (or get new ones) and make them white. Hope this helped!