3. The Silurians
Now don't get me wrong, I love the Paternoster Gang as much as the next guy, but I can't help but think they may have ruined the Silurians and Sontarans. It's made clear that the Silurians are not happy that humans currently inhabit the Earth. So for one of them to be on the side of humans kind of ruins this aspect. So unless the Silurians return to battle Madame Vastra, it won't work... Especially when a Silurian is actually married to a human! I would like to see Madame Vastra again of course in the future, but not the rest of the Silurian population. When Vastra is no longer on Doctor Who, the Silurians may make a return. This brings me to...