Adaptive animation is another of the current frontiers that builds on realism. After that, probably AI/Behavior that results in more than a simple choice between pre-canned responses that are blended at best -- something more natural than that will be needed to cross the uncanny valley once we reach realistic-appearing humans in real-time..
+1 on mentioning animation. It's too often overlooked. Maybe we shouldn't talk about "photorealism" but "movie-realism".
On that note, lighting is not only about bouncing in the world, but also how light interacts with a camera.