This is more character-specific than all-encompassing, but I've been thinking ever since we started that at some point, someone with telepathic powers and a dastardly bent could tear down the wall in Daine's mind that keeps her from forgetting she's human.

Because hey, then we could have a feral shapeshifter running/flying around the park! IT WOULD BE FUN. And the Doctor/TARDIS could probably replace the wall or put up something similar, at which point she'd be appalled with herself. And also depressed because the original wall was Numair's work and now it's gone bawwwww