I've come to my own conclusion that the only things that really seem of consequence anymore are:
Tier 1
- What happens at the Wall/John Snow/Nights Watch/The Others
- What happens with Dany and her dragons in Essos, and how that will play in to the above
Tier 2
- Bran
- Arya (which may still end up inconsequential but at least the series is pretty closely following the books)
Dorne doesn't seem to matter.
The Ironborn don't seem to matter.
Manderley doesn't seem to matter.
Aegon doesn't seem to matter.
Quentin Martel obviously didn't matter.
The Riverlands doesn't seem to matter.
Sansa, Jamie, Brienne, Bron, and Littlefinger are being used as a clean up, to omit or alter characters and story lines and just keep the series moving forward and close out story arcs. Granted, Kings Landing is following the books pretty closely but at this point, without an alliance (Dorne/Aegon/Varys) forming to move against the Lannisters/Tyrells, the happenings in Kings Landing seem almost inconsequential.
I'm not griping, its actually pretty fun to have some surprises. But they (they being Martin and HBO) told us that they would go different paths but end up in the same place and they obviously were not joking. And as much as I have enjoyed the books, it does leave the reader wondering what all the fuss was about. In the end it is going to be dragon against The Others, fire vs. ice, and the rest was just thousands of pages of glorious characters and detail. IMO of course.