Debugging data binding is hard. There could be a tighter coupling and type safety between view model and view. MVVM could be better integrated. The syntax generally could be simplified (MVC did this when they introduced Razor). There is a lot of room for improvement. The foundation is very good but very hard to learn and you need a ton of obscure little tricks.

The .NET 5 doesn’t address any of these. They do a lot of good stuff for server side development but the story for desktop development is bad.