I have this slight suspicion Arya may be done for this season. My reasons as follows:
1.) Arya has the 'kickass' opening scene of the first episode - I've read that this was a last minute change, but this would be a very fitting opener if this was indeed Arya's last season.
2.) The Ed Sheeran appearance is supposedly a 'gift' from D&D to Maisie Wiliams - the backstory being that the showrunners had been trying for awhile to get him on the show at her request, which is at last fulfilled. To me, the scene overall leads me to believe it is actually a parting gift to the actress.
3.) The surprise reappearance of Hot Pie - obviously a tip of the hat to their work together on the show, and the dialogue clearly indicates this is the last we'll see of Hot Pie. If Arya was going to be gone this season, this would be the last opportunity for Hot Pie to appear and say a goodbye.
4.) Goodbye to Nymeria - This scene clearly indicates there is no future plot with Arya & Nymeria together, concluding and finalizing their role together in the show version of the story.
And all of this is only two episodes into this season. I wish I could explain my gut feeling more in depth, but it seems like all of the above events that have taken place would be something that has to be done for a proper goodbye to Maisie/Arya on the show. Of course it's entirely possible this all had to be before the show ends next year in general, and this was the time to do it, but I still think there is a strong possibility S7 could very well be the last of this character.
Any thoughts? And I think this might be my first post here on this board, so please don't tear me to shreds if there are any glaring mistakes, etc. - I'm just a longtime lurker ASOIAF fan.