I'm just wondering why the Doctor hasn't been actively trying to seek out Gallifrey's location? After all, it was made a big point in Night of the Doctor that Gallifrey hadn't been destroyed, it was locked away, and then they magically gave Matt Smith a stack more regenerations, but as soon as he turned into Peter Capaldi, the quest to find Gallifrey totally slipped his mind and it's just off on more adventures with Clara...