Can't fucking wait to see how Arya becomes one of the Faceless Men. She is one of my favorite characters because of just how much shit she goes through. She goes through more hardship than virtually any other character I think, and it's made worse because she's so young IMO. She didn't want to be a lady, and she got her wish. But it turned out to be far different than she imagined it probably. Life is fucking rough.
Also, hope the show doesn't shy away from the whole mysticism/magic bit with Beric Dondarrion. They probably won't be able to properly delve into the details as much, but dying 7 times is a pretty major plot point in his character.