I have been hard at work on C++/WinRT for the RS5 release. There should be an update available with the upcoming Windows SDK for Windows Insider builds very soon. This will include most of the changes coming in RS5 and I will begin to share more about that as soon as it is available.
Beyond RS5, I am starting a new project that builds on C++/WinRT and I cannot wait to share more about that.
Please check back again soon as I will be sharing a lot more information here on kennykerr.ca regularly. I have also rather unexpectedly left Twitter. I may share that tale of woe someday, but feel free to reach out via firstname.lastname@example.org or via the comments.
If you have specific questions about C++/WinRT, please use the Developer Community.