So far, Doctor Who has been very good at providing realistic costumes for its female leads. Rose’s hair, makeup and fashion sense looked appropriate for a 19-year-old girl who grew up in a London council estate. Donna wore clothes that implied she shopped in bog-standard department stores, while Martha, a doctor from a more middle-class family, looked a bit more put-together.
Then once we reach the Moffat era, both of Amy’s jobs (“kissogram” and fashion model) were based on her attractiveness, so her casual-but-beautiful appearance made sense. But Clara’s fashion sense was always a lot harder to pin down, partly because the show failed to tell us much about her as a person. The idea of her being vain and egocentric was introduced this season, but with little to back it up except the Doctor’s many inexplicable comments about her appearance.