Arianne Martell
In the novels, Arianne Martell, the daughter of Doran Martell, attempts to kidnap Myrcella Lannister in order to crown her Queen of the Seven Kingdoms. Things do not go particularly well, the young Lannister loses an ear in the resulting scuffle, and otherwise, things carry on as they were before. It’s understandable that this subplot would get the axe, but that doesn’t mean Martin isn’t planning to follow up on this in a future book.