Is WPF dead? And what's it been replaced with?

WPF is still supported and developed. Appfabric/velocity is now Service Fabric which has much more functionality, runs many Azure and MS cloud services, and is open source.

Silverlight was unfortunate but overall good for the web. You must realize that even Flash, the vastly larger competitor, also died and gave way to much better browser native APIs.

I don’t know about Windows workflow but it’s important to keep in mind the difference between abandoned products vs the changing software trends landscape.