I agree that Jasnah is fine on her own, and doesn't need a romantic relationship to flesh her out. Also, she doesn't seem particularly interested in any romance at the moment, and is perfectly happy to be as she is. Also, Jasnah and Kaladin seriously have *nothing* in common. It's not even a case of "opposites attract." It's just a total lack of any kind of rapport or commonality.
He's emotionally driven, conflicted, stubborn and has lots of issues. She's rational, logical, strong, confident, and can't stand unresolved issues or irrational emotions.