Alright brethren, have you your trusty flame shields? Have you your sharpened axes? We must bare the brunt of danger, you youthful sinewy races! Yeah, I didn't like Game of Thrones, and here's why:
1). Pacing- A great writer once said that brevity is the soul of whit. In other words, every word, of every sentence, of every paragraph, of every chapter has to earn its place. If you read Watchmen, every panel holds symbolic meaning, and ads to the narrative. Tolkien built all of Middle Earth in maybe two thousand pages. Martin can't even reach Winter. If you add anything to the perfect story, then it becomes too much. If you take anything away than it doesn't make sense. In Game of Thrones I was literally able to skip entire chapters, entire character arcs, and not miss anything important. Case in point, Brianne. She bored me, so I wondered if I could skip her chapters without missing anything. I went through the entire fourth book, then went back and reread her sections. I didn't miss a thing, the story made sense without her. One could argue that character arcs should converge at the end, but they never do in Martins work. They grow out of control, like a weed, and then he kills off the characters in order to sever the plot threads. He doesn't kill characters because he's cruel, he just doesn't know what to do with them anymore. The plot, such as it is, doesn't really go anywhere, and when it does it moves at a snails pace. I noted the major points in every book, such as Ned dying, and found that they were few and far between. The important material doesn't usually occur until the end. As a result only the first book had good pacing.
2). Narrative focus- There are two kinds of writers, gardeners and architects. Gardner's start with an idea, and let it grow. Architects plan everything before writing. Gardening can work, but it's difficult because the writer himself doesn't usually know where the plot is going. If you don't know where the plot is going, then it's difficult to build your story towards a reasonable conclusion, because there's no direction. If you write this way then you need to constantly go back and rewrite everything so that it all makes sense. Martin doesn't do this, and as a result his writing has become a bloated mess that he can't control. He gets off topic from the main plot constantly, and it doesn't work. What's the main plot? Is it the frost zombies who we barely see? Is it Danaerys, who is STILL stuck in another continent? Is it the warring factions of Westeros? Is it the rise of this mysterious Red God? All of this should have been resolved by now. Instead, not only has it not been resolved, but Martin has actually EXPANDED it with that nonsense in Dorne. So apparently we're ripe for another civil war after the one that took three books to resolve. If there isn't a civil war, then why was it there? Basically, he writes it as a t.v. series, which makes sense because that's his area of expertise. Every book is a season, and he makes up what happens when he reaches that book/season. Unfortunately you can't write great literature that way, and in this case it's an unorganized mess with no clear focus.
3). Theme- what is this series about? No, I'm not talking about the plot, I'm talking about the message. I get a vague nihilistic undertone to the work, but it's not organized into anything concrete. He seems to feel that the world, or at least the medieval world, is a dark and terrible place, but the only way he knows how to express this is by killing off characters, which is lazy. Berserk handles similar material, but in a sophisticated way, so that you clearly understand what the book is about, and what the writers stance is on the subject.
4). Sexuality- Yes, this gets its own topic. Blatant fan service with no relation to the plot. If it has no relation to the plot, it needs to be cut. When Guinevere had sex with Lancelot, it ruined her marriage and brought the Kingdom to a standstill. When Griffith had sex with Princess Charlotte it ruined his career, got him sent to prison, got his men killed and sent into exile, and changed the lives of every character in the story. Some of these scenes were very graphic, but they were all necessary to their respective stories. This is not true for Game of Thrones, where they often read like blatant pornography. They actively detract from the story, and sometimes make characters act in ways they wouldn't normally act in order to include fan service, which breaks immersion. The fourteen(?) year old Dani is the perfect example. She has sex with a handmaid just after her family was killed, and she was supposed to be in mourning. Some fans argue that children were married off at that age, which is true, but in this case it really is just pornography featuring a teenage girl. It was never suggested that she was bisexual before this. He could have explored this relationship more deeply, but instead the issue is never brought up again. It happens again with Cersei.
5). Characters- Well written characters who never do anything. Dani is stuck in the wrong continent, where nothing is happening in relation to the main story. Brienne never does anything plot relevant. Everything house Stark did was rendered pointless after the Red Wedding. Jon is killed(?) because his brothers are loyal to their oaths, after his predecessor was killed because his brothers weren't loyal to their oaths. This is bad, since his arc was the only one going anywhere. Arya is a great character, but all she does through the first four books is get kidnapped, I counted, five times, and occasionally escape. Sansa has no character agency, and spends her time being kidnapped and having no relation to the plot. Everything Theon does is irrelevant after the Red Wedding, house Stark would fall regardless. The characters progress at a snails pace. In chapter one of Watchmen, just twenty pages, we meet every character, get introduced to the world, and have a clear understanding of what the plot is. In Game of Thrones it's still not clear, not because of excellent writing, but because of chaotic pacing.
Read berserk.