(Just a quick post while I wait for Anders's talk to start. Hope he confirms destructuring assignment.)
This is completely brilliant.
So my Windows app development paradigm in this brave new Win8 world is going to be this: all the internal logic, the Data Access Layer, the Models and ViewModels and so on can be built in C#, with type safety and unit tests and the performance gains. Then those ViewModels are exposed across the WinRT ABI boundary and bound to HTML views, styled with CSS and with all the UI-specific code (transitions, animations etc) implemented in JS by people whose idea of a good colour scheme isn't "blue".
And if there's performance-critical code, I'm going to write it in C++ using the AMP library.
Right. I'm going to watch this talk, then I'm refactoring my Github app and do the UI in HTML.