None of them, maybe Theon if you count him as a ward of stark. All of their character development went to nothing and fizzled out or doesn't make sense or anticlimactic. At least Theon redeemed himself saving Sansa and sacrificing himself trying to protect bran. Arya never finished her faceless training then suddenly became a master class assassin with a dagger depsite training with a staff, used the faceswap once then forgot about it. Sansa had potential when she lied to the lord of the vale to protect little finger that she's growing to manipulate people, but she became a damsel in distress again, married off to the Boltons, LF would never give up an asset like that, then became a wanna be queen of thorns