Well a number of them have horrific bugs in them which have zero attention. At least win32 has an abstraction level which allows you to work around them.
There’s a fun bug on WPF and form backgrounds for example which means on fractional DPI screens the background is tiled unpredictably. Had to patch that one up rather quickly one day and it was a mess due to how damn complicated WPF is.
I don't believe we'll get any toolkit without bugs in our lifetime. There are bugs in everything, but it doesn't prevent millions of different apps running using WPF every day.
There’s a fun bug on WPF and form backgrounds for example which means on fractional DPI screens the background is tiled unpredictably. Had to patch that one up rather quickly one day and it was a mess due to how damn complicated WPF is.