[A revised and improved version of this essay appears in my book The Eleventh Doctor: a critical ramble through Matt Smith’s tenure in Doctor Who.]
It’s part of the essence of Doctor Who that it drops bombshells on us. It’s a show where things are not always as they seem, and where trying to figure out exactly what’s going on is an important part of the fun. Back in the day, we were shocked by the revelation in The End of the World that the Time Lords were gone; we all guessed wrongly at the identity of The Doctor’s Wife; we were chilled by the sight of Daleks on our side in Victory of the Daleks.
The one constant that makes these constant twists and turns work is that the character of the Doctor himself is reliable and consistent, even as his personality changes between incarnations. He himself is the bedrock against which all the waves of the universe break, the ground against which we evaluate the changing figures.
MAJOR SPOILERS FOLLOW THE BREAK