Doctor Who was fantastic. This is the third finale story in a row that was written by Moffat and directed by Rachel Talalay, and they've all been excellent. I think of them all, this episode has done the best job so far of interweaving humour with horror.
I was spoiled for both the Mondasian cybermen and the John Simm Master, because they were both in the BBC season trailer. (Nice one, BBC.) Not that I cared so much, because the creeping body horror around the Cybermen plot was still fantastic (never has a volume control been so chilling), and I still didn't recognise Simm under the makeup until he was stealing up on Missy. Plus, the impact of Bill's conversion wasn't lessened. (My favourite touch - that she had to look up who she was.)
Meanwhile, I am a teensy bit disappointed with the trailer for next week, and only cautiously optimistic about "The Doctor Falls" sticking the landing. Reason being: Mondasian cybermen are awesome. I love the voices; especially in the Tenth Planet, where they just open their mouths and it streams out. The gradual addition of the design elements means they really lingered over it all. And, their last appearance on the screen was over fifty years ago. This is their moment!
But instead, in the trailer we get phalanx after phalanx of the new series Total Robot Cybermen. Which originated in a totally different universe and have zero connection to the Mondasian Cybermen. And are just not as interesting. It's a disappointing bait 'n' switch. Plus, it calls into question why they brought back the Mondasian Cybermen in the first place. I mean, aside from getting the truly tragic classic series fans such as myself to go "Squeee!".
On that last point, this episode, I think, would have to be a rather different experience for a casual viewer compared to a dedicated fan. The less obsessive viewer is going to be far less likely to be spoiled for Mondas or Simm, and will get the full effect from the reveal (especially on the former). But by the same token, I wonder if "It's the Mondasian Cybermen" would mean anything to them. Hell, it's been over seven years since John Simm last dwelt amongst Doctor Who's scenery and hungered for its flesh. There's probably a fair number of casual viewers for whom that reveal was more confusing than anything.
Fortunately, I think this ep was so well crafted that it's cracking entertainment even if you were spoiled for the two interwoven HSQ moments, or if you weren't but didn't have cause to care about them anyway. Caring about Bill is enough for it to work. (This is without even delving into the rather clever conceit of the ship's time distortion, or the utterly bonkers malevolence of the Master's plan to diguise himself as a comedy Igor, befriend Bill without her ever twigging that he's the former Prime Minister, and apparently just chill out with her making truly and hilariously bad tea for a couple of years until finally the time-challenged Doctor looks like he's about to get on with rescuing her.)
Going back to fans vs casual viewers: I do rather love being pandered to with touches like bringing back the Mondasian Cybermen (or the Macra, way back in the third season). Doctor Who is fifty years old and a very fast-and-loose relationship with canon. It has a huge amount of history to mine and a readiness to rework it whenever it makes the current story better (or, frankly, just weirder). I do rather enjoy when it just decides to let its freak flag fly. But if ever the fan service is taken to be the main point, it's going to alienate the casual viewer, and you just don't do that. If ever the interests of die-hard fans and the 'I'll watch it if it's on' crowd conflict, you pander to the latter. They're the ones who keep the show on the air. The show forgot that during the JNT-Eric Saward years, which was a large part of why it got cancelled.
Anyway. Fingers crossed that next week continues the quality of this episode, and does something interesting and unexpected with the Last Temptation of Missy.