Look at this screenshot of context menus in Windows 10 https://pbs.twimg.com/media/C2Y6rwoXEAAaQll.jpg:large win32, MFC, WinForms, WPF, Web.. Why don't stick to 1 framework and make it work good, deprecate rest, why have multiple buggy and ugly. If compare HTML/CSS and WPF improvement over last 15 years it is 10000 to 1. WPF could have been great 5 years ago, but I'm not sure it ever will be.
The philosophy of WPF is that you do all of the UI yourself. It gives great flexibility to make anything look like anything else, but it provides a subpar experience if you mostly need your app to be functional, vs winforms. And as you point out it kills any form of standardisation. What's missing to WPF is good tooling. The current tooling in VS is nothing more than an XML editor, without a useful intellisense, and…
The tooling you look for is probably Blend.