For me, Listen is the most meaningful ep of the season so far. The idea that it's not about The Silence or some other new threat but that the Doctor's vulnerability is the actual antagonist is the sort of introspective and emotional conflict we need to understand the new visage of this character.
It's worth noting that not unlike Catherine Tate's depiction of the companion Donna-- one is never confused about the relationship between this Doctor and Clara. Amy, Martha, and Rose all entertained some aspect of a crush; which was often a source for comic relief (tragic and unrequited love in Martha's case really). These ladies; Donna and Clara; manage to offer extreme comedic circumstances that are free from sexual tension during parts of the story that focus on exploring not the untold secrets of the external universe, but those untold secrets of the internal continuum that is the Doctor's character.
The only question is-- what was the thing sitting on Danny's bed?!
Many of us are wondering about that. I've always though it important for storytellers to leave audiences with questions but Doctor Who is unusually good at providing answers that leave us far from feeling spoon-fed so there may yet be follow-up on that point. The thing that mattered the most about that bed-sheet covered carrier was how Moffat used an actor under a blanket-- a symbol of childhood emotional security-- to showcase extreme fear in a being that has in the past stood up to so much more obviously frightening things.
Recall that Moffat gave us the Weeping Angels and The Silence. This invisible monster could have been another one of those baddies - which we would have no doubt welcomed - but instead it was not an "enemy" but his constant companion-- Fear. This sort of revelation seems only deliverable by the Impossible Girl. Truly fantastic.
