I know it's something people have theorised about ever since 'M'. Indeed, even before the show started airing people speculated on whether there would be a female Moriarty. But I never truly believed they would go there and was suitably floored.
I went in with some optimism about how Irene Adler would be portrayed because this show has done such a great job with Watson. Through the beginning, when she was shown as a victim, my goodwill persisted and I figured there was more to the situation, but still I didn't expect it to be rewarded in that way.
The danger of turning Irene into a villain is that eventually she will have to be defeated, which rather spoils the whole 'woman who beat him' thing if done badly. See BBC Sherlock for how to do this WRONG. The fact that Elementary also depended on Irene's feelings for Sherlock for her downfall is clichéd at this point, but doesn't come off as sexist as it could have since a) it's explicit that feelings were the downfall of both of them, not just her, b) she exhibits a lot of autonomy, agency and brilliance in the script independent of any man, which is all I wanted, and she's his NEMESIS to boot! and c) the win is thanks to Watson. Hooray for the "Heroine" (great title). Moriarty and Holmes are too blinded by each other, it takes Watson's clarity to see the solution.
Natalie Dormer was great, Moriarty needs to break out of prison spectacularly ASAP so we can continue to enjoy her machinations, not to mention the eventual trip to Reichenbach Falls. Roll on Season 2!

Toph, Sokka, young!Lin

Clara Oswin Oswald's tombstone says that she was born November 23rd 1866 and died December 24th 1892.
She shares Doctor Who's birthdate, which first aired on November 23rd 1963, 50 years ago.
She also died at the age of 26. Doctor Who was cancelled in 1989 after 26 years. There was an aborted revival attempt in 1996 that lasted a single episode.
Clara has now died twice, two versions lasting for a single episode each. But a third, 21st century version will be the one that finally sticks and travels with the Doctor.
The 21st re-launch of Doctor Who was made by people who remembered the old series and did everything they could for it to be brought back.
To spell it out further, Clara is a representation of Doctor Who, and so when she dies she shows up again in a new era while still being essentially the same. When she dies, she urges us, talking straight to camera, to remember her and for the clever Doctor to keep running.
Also, in both incarnations of Oswin we've seen, her job was attending children, as a 'junior entertainment manager' and a governess. But that's not all she does. There's a duality to her. Either scaring us as a Dalek (part and parcel of Doctor Who from 1963), or attending to the adults as a barmaid. Both children and adults love her and the whole family mourned her loss.
In 'The Snowmen', the Doctor remarks that the Great Intelligence "rings a bell". Was he being ironic, or did he truly not completely remember them?
The Great Intelligence was an enemy in old Doctor Who episodes from the Troughton era that are missing from the archives. Maybe the Doctor's memory loss is a reference to the episodes being lost?
"Doctor Who?" is a question that's being reiterated a lot in the series lately. Part and parcel of the storyline where the Universe has forgotten the Doctor? Hinting towards a storyline where the Doctor is losing his memories? Could the latter be a symptom of the former, because in Moffat's stories there's an equivalence between being remembered and existing? Then there's story of how Silence Will Fall when The Question Is Asked on The Fields of Trenzalore and the mystery of the Doctor's name being brought into the series as well. Will we see how River learns his name?
Will this stuff play into the 50th anniversary special? Where is Clara's story going? What's the only situation in which the Doctor could ever tell someone his name? Hoping to spark some speculation and theories with this post.

The fake-out at the beginning was an ace use of that bit from Study in Scarlet. A pity the killer aroused suspicion from the moment he was on screen, partly because of the actor and partly because of the logic of the previous episode and Study in Scarlet where the killer was one of the people in the background, but the story still had several more surprises in store. The show is getting good at turning everything on its head every few scenes. I liked Sherlock talking about how he doesn't like to present theories while they aren't locked down, but did it for Joan's benefit anyway (also to use her as a sounding board). He and Joan made a really good team this episode, her expertise was really helpful in his investigation, and it was great to see her in her element and learning more about her. The way these two broken people are helping fix each other is making for a really compelling dynamic. As usual, good dialogue, nice humour, and I continue to love his bee-keeping nerdery, hee. Most importantly, Sherlock Holmes is being better acted and written with each episode, getting more and more like the book character. I thought he was spot on in this one. And this episode was a great showcase for this show's Watson, and why this reinterpretation is a really good one.

On the Daleks...
I appreciate the effort in bringing all those Daleks together and the concept of a Dalek asylum. The imagery of the people turning into Daleks was fun. The conversation in the beginning between the Doctor and the Dalek mutant was nicely intriguing, with Nicholas Briggs' vocal performance reminding me of the excellent job he did in the audiobook of Prisoner of the Daleks. However, that was the last bit of Dalek 'character' and dialogue in this episode. It's disappointing that, given the chance to write for the Daleks, Steven Moffat (who can write some really good, poetic, dialogue) has them simply be brainless oversized metal pepper-pots that occasionally yell 'exterminate' throughout the rest of the episode. The most menacing thing about the Daleks is their twisted way of thinking, not their ray guns. It was a waste of what could have been an interesting Dalek story.

On the Ponds...
Oh, great, confirmation that Amy became a model. Not only did it come out of nowhere, it's like all the universe-saving had no positive bearing on her character. Moreover she gets snarked at for "pouting at a camera" and shows no pride in her work anyway.
Like the Daleks, the Ponds were very much in the background of this episode's action. I dislike how Moffat often has the companion hanging around in the background, often showing only passing interest in what's going on while the Doctor does all the investigation, and then needs to be rescued. (Seriously, this happens in The Empty Child, The Girl in the Fireplace, Silence in the Library, The Eleventh Hour, The Time of Angels, Day of the Moon and A Good Man Goes to War, off the top of my head).
The divorce thing was laughingly handled, with the whole relationship dynamic having happened off-screen and over an issue the Ponds could have tried to work through if they'd ever discussed it (what, adoption isn't an option? Surrogate mothers? Asking the Doctor for help?). Don't they communicate at all? For a moment, I thought the reason Amy couldn't have children was because losing Melody had been so traumatic, and my heart ached for her (Gillan and Darvill were excellent in that scene, and also in Amy's bitter "it's just life" conversation with the Doctor), but no. Will the show ever show any awareness of all the ways in which the Doctor screwed up the Ponds' life?

On the casting surprise...
Well done on keeping that secret! She did delight quite a bit in the role, and made me laugh, especially in her quirky intro. "I made a soufflé. It was too beautiful to live." I guessed what she was from the first time the Doctor asked her "where do you get the milk?", and I suspect a lot of people got it, if not then, soon enough what with her hacking skills and repeated mentions of her impossible souflés.
As for personality, she seemed to be all quips, which doesn't help in keeping up the menace of the story, making her seem realistic, or in distinguishing her personality from that of previous companions. She seems very much to come from the same mould as River and Amy, and it's dispiriting that Moffat wouldn't even try to do something different. And whyyyyyyyy make a joke about lesbianism/bisexuality being "a phase" WHAT. However, there's a chance she'll be a different character when we see her again, so who knows.

On the Doctor...
The beginning sequence was good and I liked Smith's acting there, but it grated for the rest of the episode. Maybe because he was doing his "epic" acting, which is his weak point (he wasn't very good in Victory of the Daleks or in his big speech in The Pandorica Opens). I'm glad that they haven't forgotten about his mission to appear dead to the Universe. The Doctor Who? thing was cheesy, but I can take it just this once. Series introductions require a bit of cheese.