My opinion of the "second half of the season" so far:
Bells of Saint John - a bit of a standard plot for Dr. Who. But, I was very happy at the end to see it was all the work of the Great Intelligence. I'd like to see more recurring villains, rather than monster of the week all the time. Also liked the Doctor exploiting the villains overconfidence and turning their own technology against them, which is classic Doctor m.o.
Rating: average DW episode
Rings of Ahkatenn - weakest of the 4 episodes so far, IMO. However, some really good things. Nice acting by the child actor, and Clara's affinity for children was well shown. Loved the mention of Doctor having visited there previously with his granddaughter. I liked the monster at the end being defeated by the infinite possibilities of "what could have been" when it was able to stomach even the Doctor's many memories... but while it was poetic, it was almost too poetic, in that I was left thinking "okay, but the those could-have-been possibilities aren't actually THERE, like the memories are." I liked the idea, but I needed just a bit more Sci-Fi handwaving and pseudo-explanation to have it work fully for me...
Rating: below average DW episode.
Hide - Solid story. Good ghost story feel at start. Neat dilemma with the stranded time traveler. I like the two "guest star" characters, who had depth and personality.
Rating: Above average
Journey to the Centre of the TARDIS - well, I nerdgasmed at finally getting a mostly-in-TARDIS episode. And getting to see all the cool rooms inside. The Eye of Harmony. Neat library. Glimpse of a swimming pool. Clara picking up the umbrella (7th Doctor's ? no question mark, but still...). A book on the history of the Time War. The Doctor's crib. Gallifreyean symbols on the stolen circuit, and Gallifreyan psychic encyclopedia kept in liquid in bottles. Basically, lots of continuity fanservice for us geeks. However, I generally don't like "total reset buttons" for episodes. I would want at least "echoes of memories from being in the eye of the temporal storm" or something, so we don't lose ALL of the possible character development from the storyline. Or some kind of lasting impact from the choice to fiddle with time to get the reset button.
Rating: above average, with bonus points for nerdy-continuity-porn, but points off for full-reset-button trope.
Both point adjustment factors are very YMMV, so I can see people liking this one a lot more or a lot less than I did.
And that's my thoughts and admittedly subjective opinions.