Tangentially related I wish there were a way to “search” within audio books. Once you’ve finished the book its almost impossible to figure out where a specific chapter or passage is if you’d like to go back.
The semantic data format people have had a point all along. Just because digital audiobooks are inspired by books on cassette is no reason the data format can't support all sorts of metadata. We could have a format for written and read aloud works that highlights every word in the text on a screen as it's read when used in the proper player software, with user notations, bookmarks, indexes, an completely searchable by full text.