Arya changed sure, but her story has been fascinating and she's still technically a Stark. Sansa the same, though her story was much slower, it's starting to pick up at this point in the series. And then of course Bran in the North. I loved all of his chapters in ADWD.
Cat as Stoneheart is the one I'll agree with. That whole situation is sort of...I don't know, sort of a weird plot move from Martin, but I'm still totally invested in Arya, Sansa and Bran.
Everything change's a metric ton, can't deny that, but I don't at all consider the Starks to be totally obliterated.