This season as been really good, its not been overally complex and we haven't been torchered with the presence of River Song, though i think we will get that "pleasure"
It has been straight forward sci-fi adventure and i love it
I think last nights episode owes a debt to the 11th doctor book Peacemaker, very similar themes with Alien weapon technology and also the Doctor's role.
This current series has been getting better with each episode. I had my doubts as I have to admit I felt the series before was trying too hard, with overly complex plots that failed to deliver. The underlying theme with River in it was annoying and tedious.
Dr Who has always been at its best when its the Doctor v the aliens/bad guys trying to take over/destroy the universe.