Afterthought: I disagree with Alt about Dany's character arc. She is not going back to where she started. She started as a frightened young girl, and has since been thrust into situations not of her making, and tried to do what she thought was right - kind of like Jon Snow, come to think of it. In the process she has been running away from what she truly is - a Fire and Blood Targeryan. Alt zeros in on this possibility - that she will return to Westros as an invading conqueror, leading a wild Dothraki hoard from atop a fire-breathing dragon. Well - that is what Khal Drogo intended 5 seasons back. But now it would be Daenerys in the lead. She has grown and changed a lot, and - as is hinted at the end of A Dance With Dragons - getting ready to unleash her dragons and savages on an unprepared world.
So this is not a circle back character arc, despite all the to go forward you must go back stuff she got from the mysterious Quaithe back in season 2.
I agree with his final statement, though, that Dany and Jon have vital roles to play in whatever the grand finale of this epic turns out to be.
2nd Afterthought: In Vaes Dothrak I was really expecting a Drogon ex Machina moment, but instead it was a Daenerys ex Machina moment, which I think is much more powerful.