The idea that the Doctor is an intergalactic pest who needs to be locked away is one that has been glanced at many times in the history of the show- and here we are again- invited (however briefly) to view the matter from the point of view of the Daleks and the Cybermen and those funny little warlike eggmen.
Is it a good episode? Impossible to say until we know how it resolves. The headless Cyberman was scarier than Cybermen have any right to be, I always like to see Romans and the Romeo and Juliet business with Amy and Auton-Rory was genuinely moving (which means it must have been well written because I don't care that much about either of them). I'm hoping some of the loss turns out to be real and unrecoverable or I'm going to feel my emotions have been trifled with.