I'm trying to think of which movies you would have seen with Keira Knightley and come away loving her. Her biggest movies have been the Pirates of the Caribbean franchise. I suppose you could like her from The Imitation Game or Love Actually but she's a minor character in those movies. And most of her other movies... Atonement, Pride and Prejudice, Bend It Like Beckham, Begin Again, Anna Karenina, The Duchess, Never Let Me Go, Laggies, A Dangerous Method... don't really play to a big audience if you're going by box office gross.
My issue with her career before Begin Again and Laggies was that she was doing a string of book adaptations that had defined characters but she played them all like Keira Knightley. Therese Raquin seems to be geared towards the Anna Karenina, Atonement, The Duchess crowd... not the one who sees her more popular movies.