Day 224: The Invasion Episode 5

A cynic would say that the only reason that the Cybermen are in this story is because they're known quantities to the audience, and it saves having to explain to an audience who the monsters are, as well as getting a boost of publicity from having some 'celebrity' monsters. The logic follows that any monster could be substituted in for the Cybermen, and that they exist purely as lackeys for Tobias Vaughn. However, the Cybermen are used well in this, with elements to their system that can only truly be found with the Cybermen. For example, Vaughn has decided that, in order to ensure that his alien allies do not double cross him, he needs a back-up plan to fully exert his power over them. He does this by introducing emotions to the Cybermen, filling them with fear and taking advantage of their emotionless state, sending them into a panic. This fully takes advantage of the background that the Cybermen have, and it seems clear that either Derrick Sherwin or Kit Pedler sat down and looked at what the Cybermen had in their arsenal and tried to figure out which would suit the story best. It means that the villains are actually being used to their full advantage, unlike in, say, The Wheel in Space, where they were just another monster thrown into the mixing pot