Sansa and Arya? Well, Sansa became Queen of the North by behaving like the people who raised her; Cersei and Littlefinger. This leaves it open for debate exactly how "good" she'll be at leading her people. Maybe she was fine before Dany came along and threatened her position but after she met Dany, her demeanor completely changed. And Arya? Arya is a crazy psycho herself. The only difference between Arya and Dany is Arya doesn't have a dragon to do her bidding. Arya is a deeply disturbed character who takes pleasure in slitting throats, creating kill lists, and falling asleep dreaming about murdering her enemies. I am a fan of the Starks, have been since day 1 but make no mistake about it-they are just as blood and power hungry as Dany became.
There are many morals to the story of Game of Thrones but one fine red thread which weaves through the entire tapestry of the whole thing is that power corrupts. It can corrupt sweet girls who go to King's Landing with a dream of marrying the prince and one day becoming a queen as well as powerful men who slay the man whom they believed to be responsible for kidnapping and murdering their lady love. It corrupted Robert Baratheon, Cersei, Sansa, Arya, Dany, Stannis, Renly, almost anyone who had even a small amount of it. At least, that's what I took away from it.