What I think is ingenious about the Snow White/Mary Margaret is the character is what Regina was always meant to be if Daniel was still alive. That, although they are polar opposites, Regina was meant to be the fairest of them all, but couldn’t due to Snow’s mistake. And Snow-if she had killed the Evil Queen in Heart of Darkness-was meant to become the new Evil Queen. The two characters are foils, but both came so close to becoming their own worse enemies.