Couldn't disagree more. I can understand people who aren't huge fans of GRRM's style of prose or whatever, but the later books, Crows and Dance have some of the most beautifully written passages he's ever written. Unsure about superfluousness honestly. If you weren't into expansive world-building in a fantasy world with political intrigue, I sort of question what drew you to the series in the first place. GRRM also left out mountains of detail out of the novels, hence the companion pieces he's put out (Dunk & Egg, The Princess and the Queen, The Rogue Prince, TWOIAF, TLOIAF). as well as plenty he's yet to release.
The show for the last 2/3 seasons or so hasn't really been the same story as the books. So I'm not sure how you can say it's the single example where the series is better than the novels. Especially if you're familiar with the material the show was supposed to be adapting during this time in the story. It's not really an apples to apples comparison anymore to me. The writing quality has taken a complete nosedive IMO.
TBH I don't have any problems with his prose, it's no masterpiece, but it does the job perfectly fine and probably fits the style of the story being told better than some ultra-polished wording. And I'm saying this only being mid CoK, when I left off before I was near the start of ASoS.
It's not that I'm not into the story, not at all, it's that I want the core story to go forward at an acceptable rate, not meander along getting distracted by extremely long winded non-core story threads... tbh he could literally rip out bleeding all of Bran's stuff after the first book and it wouldn't be missed, ditto Theon's betrayal etc etc... is it passingly interesting, sure, is it necessary for the telling of the story he's trying to tell? No. Does it hold back what should be building momentum up towards the serious conflicts at the story's climax? I'd argue yes.
What I'm really talking about is streamlining the story to just cover the core story he's trying to tell a little more - the squabble over the Throne weakening Westeros to the threat it should be preparing for from the North. The first book gets off to a good start all things considered, but then it just feels like all the momentum is taken out of the story from two onwards and we crawl along an extremely meandering path, getting that trademark unpredictability from the fact there's really no structure to the story, it's kind of hijacked historical events jumbled together into a sort of extremely unfocused storyline.
When I say JRRT left unneccesary things out, I'm talking like the whole White Council vs The Necromancer in The Hobbit, which of course has literally nothing to do with the story being told of trying to reclaim Erebor from Smaug. He also left out The battles at Dol Guldur and Dale from LotR as they weren't relevant to the story of the fellowship's journey. My argument is Martin includes this sort of thing and more, rather than trimming it down to what he should be writing about.
Well as I say I've never read beyond the start of Swords, so perhaps my opinion will change... if I actually get that far this time. But I feel that the TV series offers the same material in a more digestible format as it doesn't take so long to wade through it all.
Overall I think the book is like a precious metal ore, a good story is in there, but it's mixed up with stuff that detracts from it and would be made better if he re-focused on the core storyline rather than wandering off into expanding other far flung parts of the world. Having an incredibly detailed world is all well and good, but there's a limit to how much of it can be included before it starts suffocating the action of the story imo.