If Kathy wasn't around and the divorce went through, I would've liked for Elliot and Casey Novak to give a romantic relationship a shot. Casey started to work for SVU during season 5 as the ADA until the end of season 9 when she was disbarred for violating the Brady Law. Elliot and Casey knew each other before when they played against each other's baseball teams (cops vs lawyers). When Casey joined SVU, she got off the wrong food by her hands-on approach but eventually worked well together. I always thought Casey got along better with Elliot better than with Olivia. Casey and Olivia did try but they've butted heads so much so that Olivia went as far as reporting Casey to the DA. I have heard that Christopher and Diane Neal enjoyed working together. I've always enjoyed their episodes: Blinded, Impulsive, Poison, and Haystack. I was sad when Diane left but she did return during season 12, Chris's final season so they got to share an episode. Casey did return a few episode in season 13 after Chris left.