Okay, I just watched it and rather enjoyed even. Even though parts of it made me cringe.
First comment, though, is that I noticed a HEAP of Patrick Troughton (the 2nd Doctor) era references in this episode. Not least of all: The Doctor's new (and thoroughly AWESOME) costume. Granted the awesome classic-style Doctor Who coat rings closer to Pertwee and Hartnell than Troughton, he does have the funny top-hat and checkered trousers that ring more of the 2nd Doctor. I've always thought his hair was a fun call back as well.
This 11th Doctor episode is "The Snowmen" and features The Great Intelligence controlling Snowmen. The 2nd Doctor had an episode called "The Abominable Snowmen" about The Great Intelligence controlling robotic Yeti in Tibet.
The companion, Clara, is featured as a Victorian girl who works in a mansion as a governess to two children.
The 2nd Doctor had a companion named Victoria Waterfield who was a Victorian woman who lived in a mansion. She looked fairly similar to Clara in many ways.
Clara first appeared in "The Asylum of the Daleks" and she died in it. Victoria first appeared in "The Evil of the Daleks" and her father died in it.
Doctor 11 refers to the Sontaran as a potato-head. Doctor II's companion Jamie MacCrimmon described the Sontarans as being Potato-headed Hobgoblins.
Meanwhile there is also the obvious reference to the 4th Doctor from "The Talons of Weng Chiang" who dons the Holmsien Cloak and Deerstalker and creates a surrogate Watson out of Professor Litefoot.
Incidently, since "The Snowmen" takes place in 1892 and "The Talons of Weng Chiang" takes place between 1889 and 1901, it's distinctly possible that the 4th and 11th Doctor near-miss eachother. That and the 11th Doctor has been hanging around long enough to possibly run into or meet Jago and Litefoot. Heck, this is ripe for a Lady Vastra and Jenny Flint/Jago and Litefoot crossover... Hmmmm...
A glance at the Wikipedia article on "The Snowmen" reminds me that the Doctor II episode "Web of Fear", which features the Great Intelligence and the Yeti (Abominable Snowmen) takes place in the London Underground, which the Doctor points out to the GI is a weak point, setting in motion the events of his past episodes.
Anywhoo... that was all cool stuff. What I *didn't* like about this episode was mainly what annoys me about a lot of the Moffatt episodes. Another ravenous female sexual predator harassing the Doctor and making a buffoon out of him.
Please stop. Please. We get it, Moffatt. You've got a crush on the Doctor and you want to have his babies. Please let someone else write the female characters from now on. How about an actual woman? Thank you.
Oh... that and the mystical magical power of Christmas. I guess all the non-Christians are doomed since they can't be saved by such things as a family crying together on Christmas.
"Goblins are evil too, Dad."
"No, son. Goblins are just... sorta bad."
-Bob & Ben