well, let me put it this way ... if you were to watch lot of documentaries about gazelles then you probably see lions in a lot of them, cheetahs, leopards and crocodiles in some, jackals and hyenas in even less and possibly a python or an eagle in even less
see where i'm going with this? more or less the same applies to dr who and whichever villain
I mean at this point if starts to feel more like, "These Daleks, remember them from last year? They still are evil nazi trashcans!" or, "Hey now! Weeping Angels, ooooohhh, you better not blink!"
Just keep mixing things up, hell revisit an old topic like the Valeyard or something, lets just not keep falling back on the Daleks.