Just some thoughts from MS announcements so far:
- Universal apps: WinRT now available on WP 8.1 is very big news. A lot of the code can now be shared between Windows Store and Windows Phone Store apps and VS project system has also been evolved to make it easier. “Universal apps” are not really a single package. You still generate and upload different packages for say Phone and Windows Store but that is just an implementation detail. Code sharing and unified API is the big news.
- Direct3D 12: Still very few details, particularly for compute. I do hope they have substantial new DirectCompute features, particularly so that C++ AMP can evolve, but no announcements so far. MS has not committed on exact OS support yet but looks very likely that Windows 8.1+ will definitely be supported. Windows 7 is “under consideration”.
- Sandboxing and third-party JITs and interpreters: I think the situation here is unchanged. Third-party Store apps still don’t have access to appropriate memory APIs for security reasons so third-party JITs are still not possible. AFAIK interpreters exposed to users are still not allowed in Store either. So forget being able to distribute Python as a Windows Store app. I guess I am a niche here, but as a compiler writer and programmer this still bums me out. As far as developer tools are concerned, Desktop apps is still the way to go.