I think the fundamental design flaw with the scale all screens approach that wayland(and mac and X11 when set that way) employs is that your application is unable to have better dpi aware rendering. however that may actually be an advantage because it means your application does not need a better dpi aware rendering engine, that is things just work everywhere, it may look theoretically worse in it's scaled context, but at least the application writer does not have to do anything so everything just works.