Pretty much every season since the return in 2005 has had a couple of less-liked episodes, & I agree that a couple since the specials haven't really hit for me, BUT, I've enjoyed seeking out the overall arc clues in all of them. Much like trying to spot the different appearances of Rose during season 4.
I'm always here to discuss theories & such, so here are the storylines I'm invested in...
1-14 invoking the salt-binding with the aliens at the End of the Universe seems to have opened reality up to something nasty.
2-Why is Susan Twist playing different characters, & why is she in every time & place we've seen so far?
3-What does Ruby's neighbor know about the Doctor & TARDIS, & why & how?
4-& of course, who is Ruby & what abilities does she actually have, because so far, she seems to be able to unconsciously manipulate time & reality to an extent.
Anyone have any other questions, answers, or theories?