Which is why it's weird that between extending existing interfaces to include more features and migrating old stuff to newer, better, shinier intefraces they choose neither and yet somehow manage to cut your options. I don't mind the new Settings app, except for the fact that it doesn't have all the options from Control Panel, many of its links open those legacy windows, while some of the CP categories redirect you to Settings. Here's something I encountered recently: I have two montiors and use multiple virtual desktops. I wanted to set different wallpapers for my monitors, but the only option I saw was to set them per desktop. So I had to kill them, then set the wallpapers per monitor, and then set up my desktops again.
I've never had to interact with WinAPI directly, so all my complaints are coming from the user side, but I can't imagine that development experience is any better.