I am sure someone will build a title block that does exactly what you want.
Shouldn’t be too too hard to try yourself if you wanted.
I doubt it would ever be part of WordPress Core as you can’t add content above the title currently without custom development and it may be confusing for some. But it is possible to do on your own via a plugin 👍
Yup, my take has always been just because WP improved its editor doesn’t mean you have to use it 🙂 ACF is still a great solution for custom content. In some cases it may not be necessary, but I think a lot of sites will continue to use it.
Remember, Gutenberg is not an ACF or Page Builder replacement. It is just an enhancement of the current editing experience 🙂