I like that idea and I’d like to propose some related ideas for roadmap consideration.
Add a checkbox to the Edit Image dialog box that allows you to specify a specific image on the page as the og:image. Sometimes the first image on the page, even in a valid editable area, is not the preferred one.
And also show the og:image in the Edit Page Details page, like in other content type editors. This could show the auto-selected image or the one chosen by my previous suggestion, and allow you to either clear it and revert to a global image or choose an entirely different image from the library.
I know these are big asks, but hey, I can dream, right?