I welcome the change as we may see minecraft move away from Java and it's inherent limitations and flaws. With Microsoft acquiring mojang minecraft has the potential to grow into a true monster greater than it currently is. With proper mod API support as I can say one thing Microsoft espouses in their game development is universal uniformity. So we may see new mod packs/mods released that will work even better with core giving us greater stability. As a developer I look forward to the chance to work on minecraft using the xna architecture.