It’s perhaps surprising Kim Cattrall hadn’t yet headlined a soap opera. As Samantha Jones on “Sex and the City,” her slyness and way with a pun came to be revealed as elegant concealments of the character’s deep need. In later seasons, as the protective shell was stripped away, Cattrall showed a fluency and depth in playing a character whose breakability provided some of the show’s deepest and most satisfying melodrama.