Stage Manager not intuitive? Not sure about that. But the way windows jumping around, and resizing has more to do with how Apple hasn't given devs more tools to scale them properly.
Actually it’s because fundamentally Apple decided that they should auto-magically position windows to help prevent you from loosing a window. Developers shouldn’t be in charge of window position, users (via the window manager) should.
Never said they can't understand... Stage Manager is on the iPad to provide a resizing window environment, but Apple kept App Expose on the iPad due to its familiarity. App Expose is feature iPad users are familiar with... you might not like it, but plenty of iPad users do.
App Expose as you call it (multitasking switcher as I call it) is great, and my version of Mission Control is just a small rework that both helps you more easily see where you are (because the current app or Split View is slightly larger) and supports a seamless addition of resizable spaces.
If you want to see everything, then that's when App Expose comes into play. Would I like to see your concept on an iPad? Absolutely! It's dope... but I think Stage Manager is not as horrible as you make it out to be.
I can’t use stage manager because it breaks App Expose/multitasking switcher view. I like and rely on App Expose/Multitasking Switcher and the fact that Stage manager breaks it is why I hate Stage Manager so much. (I also don’t like that you can’t have separated spaces but that all ‘app groups’ are essentially part of the same stage manager area but that is minor compared to the breaking of the multitasking switcher).