What problem does this address?

In thinking about the "Why" issue #30904 I though about my initial experimentaion with WordPress many years ago. I remember the Featured Image being rather confusing: "does it show up in the header?" "why doesn't it show up in my post?". Especially now with Gutenberg it could be a much more powerful feature.

Having worked with many designers it is actually a source of frustration to build a theme with lot's of nice images in say a recent post list or archive only to have those images eventually disappear after most users don't remember or simply wont bother to use this great feature. It may even be a prominant part of the design which is then lost.

I believe with some modifications we could actually make a large chunk of the web a more beautiful, colorful place.

What is your proposed solution?

1. When adding an image or background anywhere in your page or post for the first time I think it should automatically set that image to be the featured image.

It could give you a warning:

"Image set as Featured Image" [undo] [choose featured image]

In general though I really think it should be the default perhaps with an option to turn it of in the settings. It takes away the pain of having to remember to open a dropdown in a little side panel somewhere and choosing yet another image or the same image you already put in your post. Then when the user adds an archive page or a recent post list they will actually see the images they added to their posts and not need to be reminded or encouraged to add a featured image.

2. Every block containing an image (even a background image like cover) should have a little star icon that when pressed sets that image as the featured image. And when you uncheck the little star icon it should allow you to choose a new featured image.

Rough draft of the selected state:

(Unselected the star would not be filled)

This will make it very quick to pick any image on the post or page as the featured image.

This Brings the Featured Image to the forefront and fits in well the new Block Editor as well as the Full Site Editing experience.

Finally when choosing a new featured image it should:

• If there are other images already added in the page or post show those first.
• If there is none or only the existing featured image show the image library.
• Give an option to upload a new image.
• Cancel if you don't want one yet or want to keep the existing one.

Other ideas that could be added in the future:

• Allow setting a default featured image for categories or custom post types (that could change once you add your own images) This would mean even when no image is added there would still be something.
• Allow the use of video stills or generated thumbnails of pdfs, etc.
• Allow the use of icons.

This might also address some of these issues:
#27617 Rethink "Featured Image" in the context of blocks
#30904 Featured image setting: explain the why
#24660 Allow using featured image as background

I would love to get some feedback, especially from @jameskoster