It's the best modern language overall (if you count everything: IDE, APIs, language design, cross-platform capability, capital backing, reach, approachability).

Also XNA is reborn as MonoGame. Microsoft wants to decouple from it's APIs and tools by offloading to OSS and third party (Unity3d).

C# lets you develop games that run on Windows, OsX, Linux, Android, iOS, Windows Phone, Xbox and PS, while sharing all non-UI and parts of the UI code.

I think this is 90% a result of Unity.

Let's hope Unity will support Rust, too, then...and I guess Go now as well, if Google says they want it for games.

Likely not - C# seems here to stay on Unity3D, but speeding up execution through tools like IL2CPP seem most likely.

http://blogs.unity3d.com/2014/05/20/the-future-of-scripting-...

Unity only supports managed code unless you have Unity Pro, and its not clear to me how well you can use other languages; I think the support may be more for middleware libraries and such.

Would they have to be ported to Mono to be used for Unity?

They don't even support the latest version of C#.

Good desktop integration alongside P/Invoke, meant many game studios started moving their game building tools from C++/Qt/MFC to C#/Windows Forms/WPF.

So this way C# got a foot on the door, long before XNA and Managed Direct X came into the picture.