For a super basic idea, imagine a Chrome plugin that creates an Anki deck out of a Wikipedia article at the click of a button? (Maybe not the most useful application, but pretty neat and a great place for a simple proof of concept.)
And what if you took that a step farther and made an app that does the same thing with text extracted from an image set. So you could take pictures of a textbook page or pages and have it do the same thing with those.
Of course, there are many practical challenges to developing the NLP process in a way that it can identify the most salient parts of a text and capture flash-card-friendly phrases or factual statements, but I think the challenges could be overcome. And it would be an amazing feat to capture the benefits of spaced repetition without the upfront cost of manual deck creation.