And, to be entirely honest, the episode is much more interesting before The Doctor turns up (about 15 minutes in, probably the longest we've ever gone without him making an appearance). A Gothic mystery set in Victorian England, although set in Yorkshire rather than the more usual London (The Doctor has previously visited on The Evil Of The Daleks,The Talons Of Weng-Chiang, and obviously Gatiss's own The Unquiet Dead).
Diana Rigg was also really refreshing as a villain. After several weeks of beautiful looking alien monsters who were let down by being underwritten it was great to have a villain who, despite being just a human, was far scarier than any of them. She was paired with her daughter, Rachel Stirling. This is the first time as far as I'm aware of such family casting and their real life family dynamic added another layer to their relationship and made her utter disdain and disgust for her blinded daughter seem even more evil.
Matt Smith seemed more than happy playing second (or more precisely fourth) fiddle on his own show, a sign of an actor who is comfortable in his role. Although, it must be said that his Northern accent was a lot more convincing during his ninth incarnation.
Gatiss is clearly a fan and the show would be more than safe in his hands.
In fact there was a lot of humour in this episode. Strax was responsible for a lot of it, but my favourite joke would have to be a toss-up between Thomas Thomas the human Sat-Nav, and The Doctor talking about taking a very long time to get a gobby Australian to Heathrow (a reference to Tegan, who travelled with the fourth and fifth Doctor between 1981 and 1984).
The humour was needed as there was also a lot of horror and creepy moments in the episode. Gatiss balanced them very well, hardly surprising considering his previous writing credits on The League Of Gentlemen and Doctor Terrible. Frankly, if Moffat is thinking of moving on I don't think he needs to look too far for a successor - Gatiss is clearly a fan and the show would be more than safe in his hands.