Would be really cool to have something baked into to directly suggest alt text to media when it is missing on other people's posts, as an evolution to . With dedicated notification. Apps could support the feature with a neat side-by-side media and alt text field, and one-click "accept suggestion" in notification.
I'm using @Tusky and even though I enjoy suggesting alt text, not being able to write the post with the image clearly visible makes it too difficult.