I think the latest series (s9) was the best series in years! Missy was superb, Skaro, that long conversation with Davros, the speech at the end of the Zygon episode, the episode where Capaldi acted alone for 45 minutes, the 15 minutes at the start of the final episode where he didn't say a word, yet controlled everything around him. All superb stuff. The only real misstep in my view was Mark Gatiss' Sleep No More (then again, I never like Gatiss' episodes), and the underwater base two-parter with the ghosts was a little weak. Definitely consistently the strongest season for a long, long time.
One thing I really hope is that Capaldi stays on for a bit longer. He's settled into the role now, and he's doing stuff that no other actor is quite strong enough to do. Tennant or Smith couldn't have pulled off that silent stretch at the start of Hell Bent. They're both great, but Capaldi is such a strong actor, and this year (unlike last year) he got the right scripts.