For me, the only real turkey in the season was Kill the Moon, which just didn't work. It was too full of Bad Science combined with a sufficiently familiar setting.
Next, episodes which fall into the Ofsted (OfWho?) category of "satisfactory" - i.e. not bad, but not really good enough. In the Forest of the Night had some CGI that reminded me of a Scientific American article on how city structures would fare on being abandoned by humans; but on the whole it was one of the less successful "solar flare" stories from over the years. The Caretaker borrowed perhaps too much from the K-1 robot.
Listen explored some interesting themes, but wasn't as good as Hide from the previous season, which for some reason I have decided is the most comparable. I suppose it was necessary to introduce the TARDIS' telepathic interface for later in the season.
It must be difficult to come up with an original Dalek plot these days, so credit to Into the Dalek for that, but the military coldness didn't draw enough distinction between Daleks and humans.
By contrast with the episodes above, two exceeded expectations: Robot of Sherwood and Mummy on the Orient Express both turned out much better than I'd hoped. The first was a fun historical romp, and the second extracted a better plot and conclusion than its premise implied. And of course, as throughout the season, there were all those nods to classic Who - the Tom Baker voice, the jelly babies ...
Flatline had quite a good plot, obviously somewhat inspired by Flat-Land. Perhaps it was a bit disappointing that the disagreeable character was one of the survivors. I liked the "siege mode" turning the TARDIS into a Pandorica. For completeness, I'm listing Deep Breath at this point in the running order.
Dark Water and Death in Heaven produced the goods for the season finale. Again, I liked the obvious references to previous classic and new stories, especially to Tomb of the Cybermen and Invasion in the first part; the return of Osgood, Kate Lethbridge-Stewart, and the portrait of the Brigarier in the second. Like most of the Internet, I disagree with the decision to kill off Osgood. Michelle Gomez had a rather better story than John Simm, though it did have quite a bit of Total Bollocks Overdrive; I did mostly enjoy her flirtatious and over-the-top performance and the range of accents (including of course the Glaswegian!). When she started camply referring to "My boys", I thought of Beryl Reid's performance as Connie Sachs in the BBC's Smiley dramatisations - which in turn links to another Cybermen story, Earthshock. No doubt Missy or the Master will return at some point in the future.
I'm assigning the number one spot to Time Heist, mainly on the grounds of originality. It wasn't too difficult to guess the identity of The Architect, but it did take a bit of thinking and re-thinking to follow the plot through.
The trailer for the Christmas special didn't look promising, but that doesn't worry me too much. One thing was right, though: the season certainly didn't provide a satisfactory conclusion for Clara's story. In the titles for Death in Heaven I noticed we had Clara's eyes and Jenna Coleman listed first - obviously to tie in with the deception she was playing with the Cybermen, but also perhaps to highlight the possibility that as she is so inextricably linked with the Doctor's entire timeline, who is to say she isn't in some sense the Doctor? After all, Rule #1, part 1: the Doctor lies; part 2: Clara lies; part 3: Moffat lies. All the mutual lying, and the (unnamed) boy, is unfinished business.
All in all a good season.