Another wishlist idea I had was it would be cool if when you have the maintenance/builder mode active, but you 'open' a form there was a button next to the builder button or a 'devbar' available on-screen that would allow you to see the current active form states or variables and toggle them, or to simulate a role to see what a front-end view of a form might be like without having to disable builder/maintenance mode and re-log in as an example user, test then logout and re-login as the admin user. Bit like being able to toggle various css pseudo classes in browser devtools.
I acknowledge this might go against your design thinking around separating the form builder mode from the front-end rendered mode of forms too. Would save a bit of time, but I have no idea how complicated that might all be to implement! 😃
I guess the alternative is to setup some regular fields bools/variable inputs to toggle form states manually when testing.