I also will say I really did not like Sansa in Season 1 -- she was everything that can be wrong with privileged proper princesses, and her head was in the clouds. I feel bad that her whole life caved in, but it wrought a remarkable change in her even if it also crushed her for a long time. She's never been crafty, or overly manipulative, she seems kind of slow and simple and lacking insight at times, and she can be envious; but she also maintained her dignity in an emotionally devastating situation, and I liked seeing her start to joke around with Tyrion a bit in the last few episodes. She also showed great sympathy for him when Joffrey kicked the cup under the table. And that little moment when Joffrey dumped her, where she thought no one was looking? It was very cute.
I think she is showing some strength of character in there, it just takes her longer to reach certain insights; I think she is remarkably loyal and dignified, personality-wise, and honest.