Read original post at Rodrigo Díaz's Blog
Since Microsoft has decided that “XNA is mature enough” and Shawn Hargreaves has moved to Windows Phone, it looks like we won’t see a version 5 that supports Metro-style applications. The only alternative for graphics programming is using pure DirectX 11 now that it has been merged in the Windows core (no more separate DirectX SDK downloads, yay!) and Microsoft is going to actively promote it (Visual Studio 11 includes a nice node-based shader editor).