It was called Ext-OS and based on an improved COM API, called COM+ Runtime.
https://blogs.msdn.microsoft.com/dsyme/2012/07/05/more-c-net...
So with C++/CX and .NET Native built on top of WinRT, Microsoft has gone full circle back to the original idea.
Personally I enjoy developing UWP (started right away with the old Windows 8 model), because it offers me a modern OO API to Windows, similar to the OS APIs from Xerox PARC and ETHZ OSes.
Also, sadly Microsoft torpedoed the whole WP eco-system, but the tooling is so much pleasant to use than Android's.
I also welcome the container model to put some control into the mess that is installing Windows applications.
There are lots of projects using C++/CX on Github.
https://github.com/search?utf8=%E2%9C%93&q=C%2B%2B%2FCX
Edge HTML is UWP based.
Gears of War: Ultimate Edition, Rise of the Tomb Raider, Quantum Break, and Forza Motorsport 6: Apex (Beta) are all UWP games.
Am I the only one who still likes Windows Forms?
When I have professionally-made UI design on input, and need to make GPU-rendered GUI — XAML is the best technology with the competitors far behind.
Have you ever tried to use any web design tool capable of matching Blend for UI design?
XAML is what web could have become if XHTML and its sublanguages had been adopted properly.
I doubt the performance improvements are significantly different. It's really about portability (Windows Store) and latest Windows features (start menu, menu bar, Cortana, ink, touch, high dpi)
Also, I hear if you do have an exiting WinForms/WPF app, you should be able to upgrade it to UWP.