Although in the early days of Nu-Who there was a tendency to fall back onto London council estates, at least it meant the human companions of the Doctor (who at the time was incredibly cagey about his past) had some back-story. It may have not been the most exciting (see Martha), but at least it gave audiences an in to the sci-fi action. A key element of Clara's initial character was that she was just an ordinary girl. And how did they show us this? They didn't, we just had the Doctor running around telling us "SHE IS AN ORDINARY GIRL". Clearly she wasn't and we had nothing but a leaf to suggest otherwise. When it turned out she was destined to save the Doctor is was far from a surprise. This is made all the more infuriating when subsequently a lot of effort has been put into showing us Clara is a strong-willed teacher; an ordinary person. It wasn't just her backstory that was unexplored; observant fans will have noticed Jenna Coleman's character was described as a control freak in Deep Breath, despite there being absolutely no previous evidence for that. With Amy her disjointed home-life was the central mystery of the show for a whole series, but that shouldn't set a precedent for ambiguous characters.
