If i was in charge at MS, I'd go full return to monke and put a lot of devs into making winforms work great with 4k and high DPI. Then rebuild the most critical apps with winforms using a new layouting engine and some wpf concepts carried over. Nothing new or fancy, just old but gold.
History shows that there have been many Microsoft executives with a vision of building a new, perfect GUI toolkit. They all were released half done and quasi supported to this day.