The next big thing might be the separation of UI and core program logic.
An example of this is what Nokia's Qt is heading towards: QML for UI (which is similar to or might even be a subset to Javascript, I am not sure) and Qt for the program logic and actual implementation of functionality. This is a powerful approach and it has many advantages that I think most Slashdot reader know.
This might a new (optional) strategy for Microsoft applications, HTML5/Javascript for the UI and .NET for the implementation.
Disclaimer: I am an expert in neither Qt/QML nor HTML5/Javascript/.NET and what I am saying is just a thought, and I haven't heard about Microsoft (or anyone else for that matter) saying that this is what they are aiming at. I just wanted to share a thought.