In an article written for New Statesman on the 30th of June, 2013 Laurie Penny suggests that Amy Pond, Clara Oswald and River Song all fit the definition of the Manic Pixie Dream Girl and are therefore lazy sexist tropes, rather than characters.
For illustration purposes here is the Wikipedia page about the character trope: http://en.wikipedia.org/wiki/Manic_Pixie_Dream_Girl
The main problem is that the manic pixie is a bubbly, quirky, feminine character who teaches the male hero to embrace life and explore the wonders of the universe.
With Amy this quite opposite. When we meet her in the 11th hour she is a grounded character who believes her encounter with the Doctor as a little girl was just a fantasy. This has obviously had a huge impact on her, refusing to entertain the fantastical out of self-preservation.
While we eventually learn she is a kissogram we are initially led to believe she is a no nonsense police woman. When we do learn that her true vocation it says a lot about her cynical outlook. She knows she is attractive and uses to make money. While she is engaged to Rory it is suggested that at this point in her life she might not even truly feel love.
It is the Doctor who is quirky, eccentric and makes her believe there is more than just the little village of Leadworth. When she was a little girl he was the Mad Man In A Box and when he re-enters her life he eventually persuades her to have faith in something more in her life.
The relationship between them is not romantic (despite the unwelcome kiss from Amy in ‘Flesh and Stone’). Amy isn’t an inspiration for the Doctor. She is an audience for him to show off. The Doctor admits as much in ‘The God Complex’.
That audience is important because it gives him a reason to care about things, to moderate his behaviour and for him to feel he is making a difference. A companion is a second pair of eyes and someone to keep his morality in check.
During her time with the Doctor Amy grows as a person, coming to appreciate the devotion Rory displays for her, the strength to survive decades on her own and becoming a parent and writer.
Similarly it Clara who is grounded and level headed. The Doctor knows she will be a good companion because she is practical and focused. That is what he needs, someone who will stop him from going into his own little world (for example living in a cloud in ‘The Snowmen’).
The Clara encountered in ‘The Bells of Saint John’ refuses to be a victim. She shrugs off her near-death experience and gets involved in solving the problem. She isn’t quirky, she is someone who is just willing to keep up with the Doctor.
By ‘The Name of The Doctor’ she saves the Doctor not through her insight into the universe but her dedication to the Time Lord. She sacrifices herself because she knows how important he is and that it is her choice to make.
River Song has always been the mature woman in the relationship with the Doctor. She knows more than him but shows him love and comfort. Yet River is also incredibly independent, refusing to submit to the Doctor, even when she knows he is right.
When River throws herself out of airlocks or from high buildings she does so not because she is a free spirit but because she knows that the Doctor will be there to catch her. She does so with a smile because she will be reunited with her love.
She is another companion whose sacrifice is her decision and her decision alone. Her impact on the Doctor is a powerful one. That as old and wise as he is there is always something more to learn.
Laurie Penny picks up on titles like The Impossible Girl and The Girl Who Waited but the series itself has pointed out how these titles hide the real person. In ‘The God Complex’ the Doctor says to Amy it is time for them to see each other as they really are.
To label strong female characters as Manic Pixie Dream Girls is reductive. To suggest that heroines who are on par with male heroes are unrealistic is sad.
These are characters who have inner lives, who grow and develop during the series. They are there to do more than just offer the Doctor moral support. They control of their own lives and determine their own destiny.
In conclusion the girls aren’t the manic pixies, the Doctor is (at least the 11th Doctor is). He falls into people lives, whisks them away on whirlwind tour of the universe and leaves them changed for ever.
He doesn’t live by the same rules that ordinary people do. He doesn’t have to worry about work, money or a place to live. The Doctor goes where he likes and does what he likes. While he is wise and full of lessons they rarely relate to how he lives his own life.
Even this is a superficial reading of the character, ignoring the incidences where the facade cracks and we see the troubled old man he truly is.
Characterisation in a campaign is important. Players must make a conscious decision whether their character is a shallow trope or has substance. There is nothing wrong with either approach.
The gift of an ongoing campaign is that players have the time to explore and develop their characters. While they might be happy to play a trope the majority of the time there is still room for the occasional adventure that explores what is beneath the surface.
Roles can also change from adventure to adventure. One week it might be the Time Lord teaching his companions a valuable lesson while the next it is the companions raising the Time Lord’s spirits.
Tropes are a handy shorthand when used positively. Care must be taken not to reduce a character to the simplest terms, to see them as more than the handy label someone might apply to them.