As expected people were greatly over-thinking things, but the ending bothered me a bit. The way that Jaquen said she "had finally become no one" and then smiled when Arya replied "a girl is Arya Stark" has me wondering if they're going to pull some twist down the road where this Arya isn't the real Arya, but thinks that she is.
Oh I hope they don't try and pull something like that. Sounds too far fetched even for this show where someone with serious abdominal wounds is now running and jumping through the city and then fighting afterwards. I mean, at least they showed that her wounds had opened back up, but still.
And yeah, I think the rumor Qyburn was talking about is the cache of wildfire that was talked about back in season 2. Tyrion knew about it, but I don't recall him telling Cersei about it. I don't remember if he mentioned it to her in the books at all.