Originally Posted by DavetheScot:
“You can have interesting attributes and character development without the companion being at the centre of some mystery. Many companions have done so - Sarah Jane, Leela, Tegan, Ace, Rose, Martha, Donna to name but a few.”
You can have Rose, but you're not having Donna or Ace. The foreshadowing of the DoctorDonna? An entire alternate reality forming around them? Their life with the Doctor being manipulated by Dalek Caan? The Wolves of Fenric?
Basically, the thing to remember is that Clara
is, as far as anyone can tell, a normal girl. Each Clara we've met is a perfectly normal girl. So was Amy, for that matter.
It's not the companion that's strange, it's the circumstances surrounding them. And isn't that the case with every character in Who? Nobody gets to meet the Doctor without some very strange events being in progress.