I thought a lot about who should play Arianne Martell, and I came to the conclusion that I don`t see her portrayed by any of the young actresses of nowadays.
There is a Chilean actress, Leonor Varela, who played Cleopatra in the 1999 adaption, who cold play both innocent, stubberned and powerful, but she is 41 years old, so the age is completely unmatched.
And I remembered that reading A feast for crows for the first time, I first pictured Gina Lollobrigida from her famous film-Solomon and Sheba to be just like the dornish princess. A pity these two are no longer young and beautiful anymore. BTW, hope HBO won`t erase her character. But I don`t think they`ll do it, she is too important.