OK, so I only just noticed the term "Cleganebowl" referring to the theory that Sandor will return as The Hound to fight his brother in Cersei's trial by combat. I don't think this is going to happen.. however! I do believe that they will fight. Here's a theory I threw about on the official forums a while ago about how I think it will happen -
I think Cersei's trial by combat will feature a weaker opponent - probably Lancel - as the Faith's champion. I believe she will bring out Robert Strong who will basically turn the opponent into a puddle on the floor - much to the shock of the Faith. I think Cersei will then retain her power and the turmoil in King's Landing will persist.
Sansa is currently set to wed - as it stands she is masquerading as Littlefinger's daughter, and as the most powerful lord here it seems like the wedding will have to take place at his own seat - Harrenhall. I think the wedding will proceed to there, but not before Cersei finds out about Sansa's location. Cue Cersei sending a force led by Robert Strong to kill her on the way to her wedding.
Basically I think there's going to be a massive fight near Harrenhall, (which incidentally is somewhere in the region of the Quiet Isle). Littlefinger's forces will be apparently overrun (Sansa's husband-to-be I think will be one of the first casualties, unlucky mate). Thankfully, the Lannister's plans were also found out (probably by a certain 7-stringed chap who's been spying on their troop movements) and the Brotherhood Without Banners charge in as the cavalry - led by Brienne of Tarth and Jaime Lannister, who finally have the opportunity to prove their oath to Catelyn.
Brienne will be wearing the Hound's helmet, given to her by Lem to cover up her disfigured face, and both her and Jaime will face off against Robert Strong. Remember Bran's dream? This is where it comes true -
"There were shadows all around them. One shadow was dark as ash, with the terrible face of a hound. Another was armored like the sun, golden and beautiful. Over them both loomed a giant in armor made of stone, but when he opened his visor, there was nothing inside but darkness and thick black blood" (Bran III)."
I think what will happen here is that Brienne will be mortally wounded by Robert Strong, and she will lose her new helm in the fight too. But before Jaime can be crushed too along with Sansa, a strange figure walks up and picks up the helm - THAT'S RIGHT MOTHERFUCKERS IT'S CLEGANEBOWL.
There may be extra points here if Thoros is killed and loses his flaming sword - I think there's a good chance of this because it not only prevents any battlefield resurrections but it gives Sandor a weapon that can kill the undead (although oathkeeper is another solid bet). I think the flaming sword would be better though because of the irony of Sandor using fire to kill what was once his brother. Anyway - I think THIS is what Rhllor had planned for Sandor so long ago.
I think there's also multiple levels of irony here that add to the drama of the scene -
firstly Sandor killing his brother with fire (as his brother hurt him).
Secondly the fact that Sandor is no long killing him in wrath; he can only win because he is finally at peace and does so defending Sansa, not for his own revenge.
Sansa finally gets her "knight in shining armor" - The very man who told her such things did not exist.
I think despite vanquishing Robert Strong, Sandor will also be mortally wounded, and will probably do the dramatic thing and die in Sansa's arms, possibly with a heart-rending "little bird" final quote - oh, and the news that Arya is alive.
Here's where the rest of it comes together. Firstly I think Brienne will currently be dying in Jaime's arms, who finally confesses his love for her, and Brienne dies knowing her oath was kept. Jaime then goes completely batshit, marches into King's Landing, confronts Cersei, and strangles her to death with his golden hand (totally paralleling Tyrion's story with the "hands of gold" that keeps getting mentioned, and also fulfilling the "valonquar" prophecy. oh also I believe that makes them both kinslayers too, they're both finally equal at this point and I believe this dichotomy is an important part of G R R Martin's writing for those two). I also believe Brienne's death is the only thing that could truly push Jaime so far as to kill Cersei.
BONUS - I think Sansa will catch Gendry's eye. Yep, I think Sansa has had her fill of noblemen and after finding out what Gendry has done for her sister will fall for the Baratheon bastard. Note Jaime makes a comment a while back about how she'll "marry some blacksmith". I don't think that quote was coincidental. I shouldn't worry too much about the lineage, it still unites the Baratheon and Stark lines, and I suspect whoever wins will be handing out the titles at the end anyway.
DOUBLE BONUS - I think there's a good chance Littlefinger will flee the battle to Harrenhall - where Catelyn is waiting for him, quite literally the ghost in Harrenhall. I think Baelish will meet her and to his horror will die screaming at her hands. Bit of an outside bet this one but I think it'd be really cool if it happened.
So, yeah. Thoughts?
EDIT - I noticed the best argument against this entire thing is that Littlefinger would not be so foolish as to leave the Vale for Harrenhall. My first argument would be that it would be appropriate for the newly ascended Lord Baelish to marry his "daughter" to Harry at his seat of power - which is of course Harrenhall. I think Littlefinger may be confident (and arrogant) enough in his plan to assume that Sansa's identity was still very much a secret, and that he was relatively safe in leaving the Eyrie for the ceremony. It would also assert his own power as a newly-founded lord to host the wedding in his own supposed seat of power.
However! There's another very, very good reason that Petyr Baelish (and Harry the Heir) should be away from the Vale for the wedding. Because if little Robert has an "accident" while they're away it would be very hard to implicate them in his death. If Robert dies, Harry walks in as the rightful Lord of the Vale, and Littlefinger can proceed with his plan to rally the North around Sansa. Also, Marillion is alive for some unspecified reason - I suspect he may be used as a scapegoat for little Robert's death also after his "escape" from the sky cells.
), and I'm going to guess that they'll drop Quentyn Martell too, maybe?