> Google has shifted entirely to GWT over hand-coded javascript for their applications.

Interesting. Source?

> It seems unlikely that MS would have worse tooling than Google, particularly given that MS can leverage their development tools (.NET + future compiler as a service).

It would not be hard to build a .NET to JS compiler as a parallel to GWT. In fact there are already a few such projects, one of them even a Microsoft one (Volta).

I would not be surprised to see Microsoft put some effort behind such a project. However there have been no indications so far.