(Spoilers All) The Mountain and the Hound: S04E10, and the books

A lot of people have been focused on other parts of this episode, but I wanted to draw attention to some very well-done subtleties in the Hound's section. In my opinion it was the best written, both on the surface and upon deeper examination.

The Mountain

In this episode, the Mountain is as good as dead. Qyburn says that he can bring him back but he will be changed. Cersei asks if this means he will be weaker, and Qyburn seems to imply that it will be the opposite when he says that the Mountain will not be at all weaker.

This is setting him up as Robert Strong. He'll be transformed by his death into something new at the hands of Qyburn's necromancy.

The Hound

In this episode the Hound fights Brienne, and after insisting that he is not a Knight he takes a tumble down the mountain (har) where he is critically injured. He, too, seems bound for almost certain death unless there is a Maester nearby. Thus his fate is almost certain.

In The Books

We know that death changes you in the books, too. Beric Dondarrion and Catelyn Stark are both changed by their death and subsequent resurrection. Beric goes so far as to suggest he was born with a "hole in his chest" because he remembers so little about his life before.

This section of the show is keeping in line with the books, then. But it also nicely displays a theme from the books that I missed on my first read through.

Septon Meribald states repeatedly that the Hound is dead and that Sandor as at rest, to the point where the Quiet Isle has many believing that Sandor is alive. Indeed, he does not seem to be the same person that once spoke about the glory and pleasure of killing. That is because his death, too, has changed him.

Summary

Even if we never see Sandor again in the TV show, he still stands as an opposing parallel to his brother. Both have been reborn, though Gregor's was a physical rebirth while Sandor's was an emotional/spiritual rebirth. Gregor at the hands of a Maester-turned-necromancer, and Sandor at the hands of a soldier-turned-Septon. Maesters are meant to save lives, yet Qyburn kills many people to make a dead Gregor walk. Soldiers are meant to end lives, and yet Septon Meribald is very intent on saving them. Finally, Gregor is more dead than ever, while Sandor is more alive.

Just something I noticed. I do think that this points to Sandor having a further role to play in the books, even if it isn't Cleganebowl ^^^^get ^^^^hype. Especially because Gregor continues to influence things after his death, so it only makes sense for Sandor to do the same after his own.