3. Meaningless Monster Encounters
No hero is a hero without some form of antagonism. This is basic storytelling logic that has existed since stories started being written. If there are other civilizations out there that can create art without conflict, then good for them. Meanwhile, here on Earth, even our real history can't exist without it. Conflict is part of humanity's fabric. So, while real-world dramas can deal with more subtle forms of both inner and outer conflict, horror and fantasy are usually bound to have evil personified by all sorts of villains and/or creatures that have been spawned by the writer's imagination. Science fiction can go more ways. You can have the obvious extraterrestrial enemies or you can create major universal or even terrestrial crises that the chosen protagonist needs to resolve. Now, it is a known fact that Doctor Who has explored and experimented with all forms of science fiction over its years in operation but no matter how many good episodes of hard sci-fi the serial can boast, fans will always come back because of already established alien-monster icons like Daleks or Cybermen. It is a Nu-Who trend to call upon such beasts even if the plot doesn't necessarily require them. Again, Matt Smith' regeneration is a good example of this. In The Time of the Doctor you have Weeping Angels that only show up for a few seconds, only to be never seen again. There are many more examples: the Zygons in The Day of the Doctor, the Cybermen in Death in Heaven, Hitler in Let's Kill Hitler... See? This is true for all types of villains: historical or invented, recurrent or episodic. Series 8 improved on this and brought forth some very interesting new monsters indeed, particularly the Teller in Time Heist and the Boneless (horrible name, by the way) in Flatline. Not only were they good but the plots revolved around them. But back to ranting, there probably wasn't a more blatant monster misuse than the whole affair with the Pandorica at the end of Series 5. Which leads to the next entry...