When it comes to creating a new Doctor, the most important thing is not the actor or the costume or the catchphrases. It's the script. Each story, particularly a new incarnation's first outing, must establish them both as a distinct character and also as the same old Doctor. Moffat nailed it both times. He recognised the incredible versatility of Matt Smith, an actor who can go from daft overgrown kid to stern elder statesman with little more than a hand gesture. But if casting a relatively unknown twenty-something as the Doctor was a risk, it was nothing compared to casting an older actor just coming off a role so distinctive it was hard to see him as anyone else. Moffat took a chance both times and, between the actors and his writing, made it spectacular. Better yet, he matched the actors to well crafted introductory episodes that made the new audience immediately accept the new incarnations. The Eleventh Hour was probably one of the strongest debut episodes for a new Doctor, setting up a companion dynamic that would prove to be indicative of the direction Smith and Moffat would take the Eleventh Doctor. Four years later, Twelve's establishment in Deep Breath was a unique and tense, if a little overstuffed, story that set the new Doctor in immediate contrast with his predecessor. Without doubt, fans should be thanking Moffat (as well as Smith and Capaldi, obviously!) for giving us the Eleventh and Twelfth Doctors.
