So its impossible to recruit her without all the tiefling killing thing - right? Sad. But as far as I know in previous games and games alike its a normal thing that you dont have acess to just any character depending on your aligment or choices. We shouldnt behave like spoiled kids who wants everything otherwise everything loses its value. Nothing metters because you can get anything you want. Forbidden fruit as to say. We crave something we cant have more and value it more. Also from game design perspective we are given a reason to replay the game as evil. Tho I personally never play evil characters if possible.