I'd be willing to guess that throughout the entire lives of Joffrey, Myrcella and Tommen, his final seconds with his only daughter would've been the most satisfying, genuine, 'fatherly' moments he's ever experienced. HIS child acknowledged him as her father for the very first time before falling foul to Ellaria Sand's poison. If that's not enough to tease the cruel side out of Jaime Lannister, then quite simply nothing can. I'm not expecting a U-turn to Dorne, but I'm certainly not expecting the issue to be dropped, and that's before we've even reached Cersei. She's already in a terrible place, now her daughter is gone and her prophecy is coming true. She's only got one child left...