Even more spoilers, obviously.

I wanted to like this as much as “Dark Water”. And I did really like it: the character beats with the Doctor and Missy, Clara and Danny, and the witty banter with U.N.I.T., were exceptional.

Kate Lethbridge-Stewart: Now that I have your attention, [gestures the Doctor forward] welcome to the only planet in the universe where we get to say this: he’s on the payroll.
Doctor [hisses quietly]: Am I?
Kate [aside]: Well, technically.
Doctor: How much?
Kate: Shush. [back to Cybermen] Any questions?

I could watch it over and over for moments like that.  

But a second viewing reminded me that for me Moffat episodes fall into two groups.  Some absolutely work on first viewing and continue to absolutely work going forward (“The Pandorica Opens” / “The Big Bang”, “The Day of the Doctor”, “Dark Water”), and some absolutely work on first viewing and continue to work on subsequent viewings provided you can let things go (“The Angels Take Manhattan”, “Death in Heaven”).

And yes, this is Doctor Who, with a 2,000-year-old alien and a magic box that travels in time and space, and once you’ve swallowed that, complaining about madly bogus science or unexplored consequences for bystanders may be missing the headline.  But at the end of “Death in Heaven”, a few weeks after all the cemeteries in the world started disgorging their dead as converted Cybermen, people are walking across a square, unconcerned.  Nobody is freaking out.  It is as if it never happened, or as if it only “really” happened with relation to four people in one cemetery.  It comes unstuck, like the Weeping Angel of Liberty stomping through the streets of the City that Never Sleeps, and nobody else looks up and stops it in its tracks?  No, because the only important people in that story are the Doctor and River, Amy and Rory.  Accept that and you’ll be fine.

Same here.  The mad notion that a drop of Cyber-pollen making contact with a dead person will build a fully converted Cyberman, somehow also spontaneously generating out of nothing powered armour, energy weapons, electronics, power supplies, and, oh yes, a jet pack?  It’s just there so that Missy can offer the Doctor an army and say “I need my friend back.”  The character beat trumps everything else.  (There’s a Paul Cornell Doctor Who story, “Goth Opera”, with almost the same MacGuffin: an airborne virus converts all in its path into vampires.  But vampires have never pretended to be scientific. With Cybermen, there’s at least a presumption that they might be, and your willing suspension of disbelief may vary when they aren’t.)

That said, let’s get back to the good stuff.

Doctor: Hush!  I’m trying to count!
Osgood: 87, I think.  [at surprised glances, apologetically:] OCD.
Missy: 91.  Queen of Evil.

Moffat said in August that he had no intention of bringing the Master back (of course, Rule One is Moffat Lies), explaining that the arch-villain coming back over and over again with a cunning plan, and never once remembering all the previous times the hero foiled the cunning plan, was stale.

So what we get instead is the explanation that fans (and Moffat counts) have built around the fact that the Master keeps trying regardless, even though he cannot possibly imagine he will succeed, and that he has always had some regard for the Doctor, going back to their first onscreen meeting in 1971:

Doctor [Jon Pertwee]: You’ve come here to kill me, of course?
Master [Roger Delgado]: But not without considerable regret.
Doctor: How very comforting.
Master: You see Doctor, you’re my intellectual equal, almost [Pertwee’s eyebrows go up at “almost”]. I have so few worthy opponents. When they’ve gone I always miss them.

Suppose the arch-villain isn’t really trying to take over the world with overcomplicated plots that (s)he must know are doomed to fail?  Suppose (s)he just on some level wants to reconnect with an old friend?  Suppose the hero on some level understands this?  Suppose the hero’s friend sees the problem with the hero’s sympathy that the hero doesn’t?  And that’s what Moffat gives us.  All of it.

Doctor: I had a friend once.  We ran together when I was little.  And I thought we were the same.  When we grew up we weren’t.  And now, she’s trying to tear the world apart and I can’t run fast enough to hold it together.

Doctor: Why are you doing this??
Missy: I need you to know we’re not so different.  I need my friend back.

Clara: Old friend, is she?  If you’ve ever let this creature live, everything that happened today is on you.  All of it.  On you.  And you’re not gonna let her live again.

And of course the Doctor has let the Master live, and it is on him.  All of it.  And the whole story of those forty-four years is laid bare by Moffat in a few simple sentences.  Including Clara’s unexpected role as the Doctor’s teacher:

Doctor: I used to have a teacher exactly like you.
Clara: You still do.  Pay attention.
– from 8.6: “The Caretaker”

(And it’s a wide-open question whether the Doctor meant a Time Lord from the Academy or Barbara Wright.)  And it’s frighteningly brilliant.

So maybe this is, for me, a third category of Moffat episode: there are clear holes, but the brilliance of the thing that Moffat cared about delivering and delivered in spades is so great that I almost don’t care.