I didn't mind the Paternoster Gang here. That surprised me, because I've felt that they're a joke that's gone on too long. Here, Moffat wrote Vastra like she's Basil Rathbone as Sherlock Holmes, and Jenny and Strax split Nigel Bruce as Watson. (They're both dim muscle, basically.)
Clara's difficulty in accepting the Doctor's regeneration was disappointing, because she, more than any other companion, knows that the Doctor can change. It's not puzzling, though; there's a scene between Vastra and Clara that makes it clear, if not explicit, that Clara's issue is one of lust for the eleventh Doctor in particular, not unlike Emma's revulsive reaction to the Jim Broadbent Doctor in "Curse of the Fatal Death." In that light, the Doctor's apology to Clara at the end makes sense; the Doctor is "letting her off the hook," basically.
I want to see how Matt Smith's cameo plays out on screen before castigating it. On its own terms, it's okay; here's one more reassurance to Clara (and thus, the audience) that Capaldi is the same person as Smith. But I feel like, as written, it saps the regeneration sequence of "The Time of the Doctor" of some of its emotional power.
I'm curious who Missy is and what she wants. And what the Promised Land is. My early guess is that Missy is Susan's grandmother and the Promised Land is Gallifrey.