I also wonder how hard it is to develop for Windows 8
Uhhh...you haven't even done one google search have you? For Windows 7, you use the free version of Visual Studio for WP7...with integrated WP7 emulator and use C#. I paid a one time fee of $100 and have developed and published 5 apps so far. Developing for WP7 is very easy and enjoyable I would say (integrating ads using the Microsoft's ad SDK is soooooooo easy).
I can debug in minutes and push out a new version in the seconds before market open
No peer reviews and/or staging deployments before going to prod? This sounds fishy...
Ya'll hear about the geometer who went to the beach to catch some rays and became a tangent ?