Doctor Who: 10 Things That Must Not Happen In Series 9

2. Forgetting About The Face

When Peter Capaldi was cast as the Doctor, there was a lot of talk about his two previous appearances in the Doctor Who canon. Indeed, it was a standard talking point in almost every interview with Steven Moffat that he had spoken with Russell T Davies regarding his 'grand theory of why the Doctor occasionally turns into an actor who's appeared on the show before' (known also as The Maxil Theorum). So fans were told as nauseum that he'd conferred with Russell, had the Maxil Theorum explained to him, and verified that it still worked as an explanation for who the Doctor was about to turn into that bloke from ancient Pompeii. When Deep Breath aired, viewers were treated to several delightful teases about the Doctor's face and where it might have been before. 'Don't worry,' the production team appeared to be saying, 'we'll explain it all eventually. For now just enjoy the mystery' (see also; 'Silence Must Fall', 'River Song', and 'Bad Wolf'). Then no one ever mentioned it again. Much like the previous comment on finding Gallifrey, fans don't need to have the mystery solved immediately. Anticipation is always better than finding out the answer. But at some point the casual viewer starts to wonder if it's a mystery not yet solved or a plot point that they've completely forgotten about. There's always a fine, fine line.