I believe I understand why Stephen Moffat's episodes are not as individually memorable this season as they were when he was writing under RTD. It's because those stories were self contained- and now he's constructing a season-wide arc. That said, the two episodes he's just given us are as scary as anything in the show's very long history. Clever too. When Moffat plots an episode he plays fair with the audience. He doesn't introduce us in the very the last moments to a button that will destroy all the daleks, but creates a situation in which the instrument of the bad guys' downfall is hidden in full view and continually referenced.
The final scene between the Doctor and Octavian was an example of how well he rises to the emotional occasion- and the sudden twist in the relationship between Amy and the Doctor was cheeky and iconoclastic. A lot of people won't like it- Dr Who's companions just don't behave like that. Ah, but they do now!