Oh man just got through sifting through the thread. Lot's of great insights and comments! Personally, I enjoyed this Christmas special very much although I felt like it was really carried by the performances rather than being a solid story. Everything just kind of happens, but watching Capaldi in his last romp was great. Partway through the episode I was worried that Bill and the Doctor wouldn't get a good moment together where she puts him in his place, but thankfully, they had a good moment together where she puts him in his place. I was pretty drained with the Capaldi era towards the end of this past season (but not with Capaldi or Bill themselves, mind you, just the episodes) and it took this moment for me to realize how much I absolutely missed them together.
I've not seen much of the classic era of Who so I have no frame of reference on the performance Hartnell, but I enjoyed him a hell of a lot. Honestly, I'm going to say that I laughed out loud at maybe half of the sexism jokes and cringed at the other half. Capaldi's reaction to them might bump them up a few points, but I was more amused at the meta-commentary on the backlash to casting a female Doctor.
Was pretty surprised to see Rusty, and after I actually remembered who the heck Rusty was, I decided I'd probably have to go back and watch that episode again before my rewatch of the Christmas special to solidify my opinion.
I'm in the 'enjoyed seeing Clara again' crowd. It was nice, it was "necessary" based on tradition, but it also looked goofy as hell. I'm not bothered that she didn't get to be physically there given the importance that 'memory' has as a theme in the story, but they could have chosen a better way to green screen her in. To be honest, it was so weird looking I actually thought for a moment they were using archive footage of her and just sticking her in there with some ADR.
I'm also confused by some of the minor details of having Bill and Nardole in the story. Personally, I've felt that Moffat stories are a bit confusing as far as the little details of how things come to be. Is this projection of Bill grabbed by Testament of her before she turns into the sentient oil? Does this mean that Testament records her 'human' death and she still lives on in another form with the oil girl? Or did she like...actually die and Bill is sufficiently dead. Also, is the Nardole we see one that got to live a long life and died tragically on that space station? Or did he die shortly after the Doctor left him? I don't even really understand that entire ending to begin with to be honest. I'm guessing the answer is "maybe? both? neither?". I know it doesn't really matter as they are just there to help tell the story, but I guess it'd be nice to know something more concrete.
And Capaldi's final speech was ridiculous. I love him to pieces, but that speech managed to be even goofier than Smith's. The things he was saying were very pretty, but it just took me out of the story that he was actually speaking them. SO long winded and overly poetic. I couldn't believe he was writhing in pain but still managing to do laps around the Tardis. I was hoping that speech would be maybe a third that long, and end with him with his hands across the console in a hunch and jerking his head up to give that closeup Capaldi stare to mirror the stare we got in DoTD. It would have been a nice callback if they weren't going to actually show him going to Gallifrey and being part of that battle, followed by the standard face/armsplosion. But instead he was able to dictate an 8 page speech and circle the control room what seemed like two or three circuits, lol. Now that I think about it, I'm genuinely sad that we didn't get a Capaldi closeup stare during the final speech at all. Dammit.
But it was still a wonderful episode. Ranked much, much higher for me than Mysterio or Husbands. Might be a tie with Last Christmas. I can't wait for the show to return. It always seems like the Doctor comes back for five minutes and then we have to wait a year to see him (and now her) again.