Count me in the camp that believed that the White Walkers would not stand a chance against the dragons until this week's episode. Drogon, Rhaegal and Viserion were able to make short work of the Wights, but the White Walkers clearly present a different sort of challenge. The Night King was able to walk right through those dragon fire flames, just like he did with the fire bombs that the Children of the Forest use. And the fact that he was able to take down Viserion was that spear was a shock. And then to bring Viserion back for his army of the dead? It changes things dramatically.
We've now seen Jon kill what, two of the White Walkers with Longclaw at this point? It leaves me wondering when he's going to make the connection between Valyrian steel and the ability to kill the Walkers.
I think that things at Winterfell are proceeding as planned. At least the way Littlefinger THINKS he has planned. I think some of the animosity between Sansa and Arya is real. It seems that now Arya is playing her greatest Faceless role ever: that of an honor bound, rigid Stark. One of the great lessons of the series was how Ned's devotion to duty and honor got him killed. And during one exchange between Sansa and Arya, it seemed that Sansa called it right when she asked why Arya hadn't attacked the Lannisters when Joffrey had Ned beheaded. She could do nothing, and I think Arya knows what an impossible position Sansa was placed in. But I think Arya is very deliberately playing the role of this unbending Stark for the benefit of Littlefinger in an effort to draw him out. And it all has to be very believable, right down to Arya not letting Sansa in on the plan. Because Sansa needs to be able to maintain the loyalty of the knights of the Vale, who came to her aid thanks to Littlefinger.