It sounds like most of the application complexity was the UI layer? In a typical app, the UI is an interface to some functionality or business logic which is th

It sounds like most of the application complexity was the UI layer? In a typical app, the UI is an interface to some functionality or business logic which is the actual value of the app. But if the application was something like a GUI builder, I guess most complexity would be directly coupled to the GUI framework. Still, in my experience, ripping out code which isn’t used anymore is a lot simpler than rewriting the things you do need from scratch.