I heard that the WPF code under the hood was jank, which might be part of why MS never went forward with it. From a developer perspective it was quite nice. I started in winform and I miss UI frameworks being obvious and straight forward. I have a rant about how to darken an image using HTML + css that despairs in how unintuitable and bodge-job the solution ends up being. WPF and WinForm were not like that, you draw what someone sees, inline, as they see it and that's quite nice.