Just finished reading last night. Lots of thoughts swirling around so I'll see what I write. Feel free to skip chunks of my post, it's likely waffling.
I can safely say I enjoyed the book quite a lot. I don't mind things dragging a bit. After all, I'm Scottish, the most boring drudgery in a book is still more appealing than the local weather. I quite enjoyed learning more about the world during the travels of Tyrion, Quent, and Victarion (with his burnt, smoking, arm of badassery!) especially finding out more about grey scale. There were times in the Dany chapters that I was getting sick of Daario. I kind of hope that the corpses being flung from the trebuchets at the end of Ser Barristan's last chapter will include Darrio, but then when Dany finds out we'll have to suffer through her grieving for him.
Overall, I'd agree with most others that the North chapters were the best part of the book. I liked how Jon's chapters seemed to show him desperately struggling to point out the bigger picture to everyone (especially Bowen and Yarwyck) and them not getting it. Most of what he did would have likely been beneficial to fighting the Others but they did not seem to get it. They seemed far too intent on keeping their old hatreds than working against a foe they know is going to kill them all indescriminately. The ironic thing is, in aFfC we have the Lannisters setting up a plot to remove Jon Snow, and the rest of the Night's Watch did it for them. I can't remember if they actually sent those troops north, but those guys are gonna be disappointed when they finally reach the Wall. Especially since they'll lose guys through the winter, and the chaos in the North just now.
Bran's chapters were very interesting, although I'm going to re-read the part where he gets visions looking through the trees. I'm still wondering if Coldhands is Benjen Stark or if Benjen will somehow turn up alive elsewhere. Also, a thought, we know that both the Lord of Light and the Others can raise the dead in some fashion, but there are clear differences. From what we know of Coldhands, it seems to me he's somewhere inbetween the Wights and those revived by red priests.
After reading aFfC I had kind of disgarded Wyman Manderly as a fat fool who had likely caved to what the Lannisters wanted, even though they were in no position to do anything to him or Davos. Now I realise how foolish I was, because he's the god-damned Merman! So great, and I loved Davos' chapters. I had not realised about the Frey pie though, that went totally over my head. Looking forward to seeing more of Manderly, hopefully White Harbor will pay the Freys back properly. The North remembers!
After seeing Stannis gather the hill clans in the North, and a brief mention by Tyrion, is anyone else really starting to miss Shagga, Timmet and the others from the mountain tribes? IIRC they were in the woods south of King's Landing, maybe they could join up with Aegon at some point. I kind of doubt GRRM would kill off Stannis, Asha, and all the characters with them off screen. I agree that at the very least the battle will open the next book. I'm sort of wondering if all the flaws with Stannis being Azor Ahai will turn out to be red herrings or people (in world) clinging too much to the old story of Azor Ahai to believe that it is in fact Stannis. It would almost be worth it to give Stannis a big I told you so moment of victory and vindication, hopefully while buggering the Boltons with his magic sword.
I'm also thinking that since Asha's remaining crew turned up from Deepwood Motte, it's entirely possible they have the news about Arnolf Karstark being on Bolton's side. If Stannis believes them and cleans house before the Boltons show up, he at least eliminates the ace up their sleeves and just has to deal with superior numbers and a poorly defensible position.
Maybe this is obvious and that's why nobody has said anything, but I get the feeling that Brienne turning up and going off alone with Jaime is a very bad thing. It just screamed trap to me. It's still not been confirmed what Brienne said when she was being hanged to get out of it, but I think she's leading Jaime into an ambush for Stoneheart.
Thinking about the prophecy for Dany, with people mentioning Quentyn being the sun rising in the west and setting in the east, I wondered about the sea drying up. Maybe that refers to the Dothraki sea, which during Dany's final chapters there was an off-hand mention of the grass turning brown and dying (presumably due to autumn/winter) which would technically be the sea drying up. Also, quick thought, was the line about the mountains something to do with them turning to ash and blowing in the wind. The place where Drogon was nesting, "Dragonstone", there was a mention somewhere about ash rising from it. Of course this could all be foreshadowing, metaphor or simple misdirection.
Ser Barristan's chapters were great I thought, showing him as a badass, his thoughts on honour and so on. Also, from part of what he said about the tourney which Rhaegar won, it seems like he believes that Ned went with Ashara Dayne, but there was mention of a still-birth so I wonder why he didn't question where Jon came from. Unless he believes that Ned Stark was a lot less honourable than just one indiscretion. Strong Belwas is awesome, goes without saying, and I quite like the Shavepate too. He's kind of like a novice Varys.
Epilogue was great, although I'm kind of sad that Ser Kevan had to go, but glad to see the Spider again. Oooh, intrigue!
Tyrion as always was great, I do really wish he would have gotten to meet Dany though. I think it'd be rather amusing if when he does he thinks that people have hyped her beauty up a bit too much.
Probably other things I've forgotten to mention, but I'll leave it there for now.