I honestly think Bran will be the one who had messed up the Mad King. Someone will have said to him,why don't you go back in time to have wildfire stored and ready and he did the same thing to the Mad King that happened to Hodor. Or the older three eyed raven would have done it and it is why he realized someone else has to take over as he messed up too much.
Again, nothing pissed me off more than the Jaime being saved at last second by Bronn and then wash up maybe 100 yards further in full plate. And how he can escape Dothraki on horses and a dragon, Tyrion no one goes looking. They assume he has survived and Bronn sets up a meeting etc. All reality is going out the window for contrived scenes set up solely for shock or dramatic effect. When I said it is Walking Dead level, walking dead ended up doing this too much. The governor despite being surrounded with no ammo by 100 walkers, survives and kidnaps Andrea right as she reaches the prison and the split second Rick looks at her spot to see her gone. I honestly don't think aside from CGI or stunt work or costumes or something that this writing will win any awards.
This is what happens when all you have is an outline of how the show ends. They're just trying to fill the rest in with blackjack and hookers.