Nymeria must figure back into her story again somehow, as must Syrio. My guess is that Arya is sent to kill Dany, but Syrio has been taken on as Danys guard. He defends Dany after Arya's assassination attempt. Arya is now a faceless dancer herself, she and Syrio fight. (awesome op for a Syrio POV BTW) but he is still stronger and she receives a near mortal wound from him and looses her face as she is dying. Syrio then has to plead her case to Dany who is every poor soul's mother and she has Arya patched up and gains a deadly little ally when Syrio completes her training. I won't go so far as to say Arya kills Cersei...out of respect for Maggy the frogs vision but the Hodor/ Mountain Robert match up is coming, Who's to say Bran is not the the "little brother" Cersei fears? It's easy to loose sight that when the dusts settles on all these little details, the ultimate battle will be when everyone unites against the Others and whites at the wall.