It hurts to say this, but Doctor Who appears to be getting old. The series, I mean, not the character. We all know the character is ancient, which helps add credibility to the poignancy of his situation. But, the 2013 season is showing us that even a Time Lord, with all of existence as his canvas, ends up painting the same pictures, eventually.
The high point of this episode was, for me, a throw-away reference to the pre-21'st-century version of The Doctor (going all the way back to the original, actually, and good for you if you caught it). But, what disappoints about that tiny moment is that it seems like it might be the start of another arc that builds on the grand structure of the Doctor's backstory, yet that's not what happens.
What happens is, yet again, the Doctor coincidentally finds himself in yet another apparently mundane situation that, yet once more, turns out to implicate extraordinary forces, dangers, and events. When these things are ultimately explained to have some connection to the Doctor and his mysterious past, they make a kind of sense and also make a kind of promise (that this is all _going somewhere_, and we'll find it satisfying when we arrive). But, when the Doctor seems to encounter them by dumb luck, one tends to feel that, when the story is over, one pretty much ends up where one started. (If one is inclined to cosmic thinking, one also ends up wondering just how many other similar situations turned out differently in other parts of the universe, for lack of the Doctor's random-chance involvement.) Successful TV series often suffer from the problem that is eroding Doctor Who: they bring you back every week because you want to know the answers to the questions that make the whole thing so fascinating, yet once you get your answers, you may not ever come back. Doctor Who is avoiding the questions in, apparently, an effort to hold off giving us the answers. Watching retreaded stories like the first two 2013 episodes, when we would prefer to be getting closer to just what it is the Doctor means when he talks about his senses of guilt and loneliness at being the last Time Lord, is starting to feel like a waste of time.