Zoe joining The Doctor on his travels is mildly disturbing, only because she tells no one on the Wheel that she's leaving. Do you think she even sends a letter after she leaves? A message in a bottle? A text message? Most of the other companions we've seen join the TARDIS over the years have had all their family and/or friends slaughtered before their very eyes, which is horrific for the companion, but it did save a lot of awkward questions.
Zoe is one of the first companions who would appear to be missed, as she seemed well liked around the Wheel (if seen as a little robotic). Mind you, the crew gets over the deaths of their controller, their chief medical officer, and a good few crew members relatively quickly. Can death be such a common occurrence on a space research station? It's enough for Tanya Lernov and Leo Ryan to find the time for some cuddling.
The Cybermen are dispatched rather easily and, in a purely visual sense, entirely unconvincingly. And why do they look so funny while walking in space? And what, exactly, are they walking on when they're walking in space? Space?
The Patrick Troughton era hasn't had many low points, and although The Wheel in Space is clearly veering towards the end of not being terribly good, at least it's still not terrible.