Ehh, so the Dorne storyline is over & done with? Was hoping that region/tribe would be more than just a tangent.
I personally think Dorne's role and the role of The Reach were largely squashed in order to simplify the TV story.
RR Martin had a whole thread about Doran Martell's (gout guy, killed by Sand Snakes, Oberyn's brother) son who went off in search of Dany and wanted to marry her and all this jazz, and I imagine that son (who doesn't exist in the show) would have brought Dorne around to fight with Dany at some point.
He also had a whole fucking thread about Rhaegar's first born son Aegon by Ellia Martell, who supposedly was killed by The Mountain during the sacking of King's Landing, but really he survived and grew up across the Narrow Sea with one of those mercenary companies, and Tyrion hooks up with that mercenary company and they land back in Westeros to try to claim the throne, just like Dany did.
I think people who have only seen the show don't realize RR Martin had like a dozen more story threads running, in theory tying together and/or including more of the 7 Kingdoms into the final outcome of the story.
Methinks the TV writers talked to him and found out many of these threads were just there to keep the readers guessing, and would dead-end (literally in some cases), and so they were not vital to getting to the major plot points that wrap up the story.
For instance, Stannis never died in the books and they ended close to where he died in the show.... but in the books he was camped near Winterfell heading North, presumably to end up helping the Night's Watch as he did in the show.... and I would not be shocked if he plodded along as a decoy in RR Martin's book story farther down the road than he did in the show, but the TV Writers likely said "Why keep having him in the story for 5-10 more episodes, when we know he is a literal dead-end?"