I know!! I appreciate that you making me quite hopeful too. I I also think that the old Hound died. And I am totally creating fanfiction here - I hope Sandor will save Brienne miraculously out of the situation she is in. The fact that they met was there for a purpose, nobody else knows where she has gone (And well, they can go ahead together rescuing Sansa).

But when I am serious I do really see how Martin singled Sandor out from the very beginning to kill Mountain. For Sandor it would be an ultimate aim. And also if not Sandor, then who? Remember what had happened during the "King's Hand" tournament? And don't think anyone will survive after their fight.