Something to bear in mind when talking about companions.
Companions were always built to be audience association characters. That’s why they’re from all different walks of life – teachers, students, doctors, nurses, temps, shop girls, scientists, soldiers, stewardesses, random hooligans, what have you.
Every companion, whether you like them or not, has at least one person out there who looks at them and thinks ‘That’s me.’ For me, that’s Susan. For some people it’s Clara, for some it’s Donna or Rose or Sarah Jane or Jo or Ace. That’s what companions are for – so people out there can look at someone having adventures with the Doctor and say ‘That’s me, someone like me is having adventures.’
This is why I get bent up when I see people say ‘Such-and-such companion need to go away’ or ‘Such and such companion needs to hurry up and die.’ I can understand disliking a companion (I have a couple I’m really not fond of at all), but imagine being the person who looks at them and, as the writers intended, says ‘That’s me.’ Now imagine total strangers saying the character who makes you feel special, the character who’s you, needs to go away and/or die.
Don’t like a companion? Fine. Believe there are legitimate critiques to be made when it comes to writing? Fine. But for God’s sake please stop snarking about how you want something terrible to happen to your un-fave and then acting like it’s witty of you to say so. Or if you’re gonna do so, at least keep it to your circle of friends, because I guarantee there’s someone out there – in many cases a child – who associates with them very deeply.