Cersei died in Game of Thrones' penultimate episode in a deeply disappointing way, which will, hopefully, not be repeated in the books. Game of Thrones season 8, episode 5, "The Bells", saw Daenerys and Cersei face off over King's Landing, and while Danerys went full-on Mad Queen and decided to burn the city to the ground, Cersei met her end underneath the Red Keep when debris fell on top of her and Jaime.
Cersei's death in "The Bells" wasn't particularly surprising (few fans expected her to actually make it all the way to the end of the series), but the way she died left a sour taste in viewers' mouths, thus partly resulting in the worst-reviewed Game of Thrones episode to date. Like so many other recent deaths, fans are furious that Cersei wasn't given the final showdown that she deserved. The Queen that has been cunning, ruthless, and incredibly powerful (nigh unbeatable) for nearly 10 years wasn't brought down by a worthy foe.
She wasn't tricked into losing her life. She wasn't killed by a valonqar, and she didn't get a decent final scene with Daenerys herself. Her death may be one of the most disappointing of the entire series, but thankfully, the books have the ability to change everything and give Queen Cersei the death she deserves.
And The Valonqar Is... A Pile Of Bricks
For years, fans have been debating who will kill Cersei, with the vast majority of book readers putting great stock in the prophecy of the valonqar. This was part of Maggy's fortune telling to a young Cersei, that predicted that she would be Queen (but not marry "the Prince"), the number of children she would have, that she would be supplanted as Queen, and that her children would die before her. In the books, it also tells her that she will die courtesy of a valonqar (High Valyrian for "little sibling") who will wrap their hands around her throat and choke the life from her.
Discussion of who this could be has covered everyone from Jaime and Tyrion to Arya and The Hound, but in the end, she wasn't even killed by a person. Instead, Cersei attempted to flee the Red Keep as it came crashing down. She was being led by Jaime to a secret pathway out of the Red Keep. Unfortunately, the path was blocked by a wall of stone, and Jaime and Cersei held each other as the building collapsed on top of them. Of course, some fans are hoping that they somehow survived this, and will get a decent death in the finale, but that's highly unlikely.
Game Of Thrones Is Ignoring Prophecies
The prophecy of the valonqar is not the only prophecy that Game of Thrones has ignored - and technically, the valonqar part of Maggy's speech didn't even make it into the series. However, Game of Thrones has also done away with the idea of the Horn of Winter (that could bring down the Wall), choosing to use a zombie-dragon instead, and it's dumped the coming of Azor Ahai in favor of assassin-Arya. All of which was fun to watch (unlike the valonqar-bricks), but it points to a bigger problem.
Doing away with one prophecy is an interesting way to make the point that it's important not to put too much stock in visions and fortunes. However, Westeros is a world of magic, dragons, and Three-Eyed Ravens, and prophecies are a huge part of that. The decision to ignore essentially every prophecy isn't one that feels carefully chosen to make a point, but that seems like lazy writing. Bran's visions were easy to bring to the show, so they stayed put. Azor Ahai and the Valonqar, however, were a little more complex, so rather than explore them, Game of Thrones deleted them.
What Was The Point Of Cersei's Pregnancy?
As well as prophecies, Game of Thrones doesn't seem to know what to do with Cersei's pregnancy, and her death proves that this is another storyline that was dumped after it stopped being useful. Cersei revealed that she was pregnant in season 7 - first to Jaime, then Tyrion figured it out during their parley. This season, she decided to tell Euron that the baby was his - yet this all comes to nothing, because she was killed off before she even started showing.
Ignoring the huge timeline issues that come with this particular pregnancy, this feels like another particularly pointless storyline, thrown in at the last minute for no real reason. It may have helped explain why she decided to allow Euron into her bed, but (other than providing some particularly creepy scenes), Euron absolutely didn't have to sleep with her in order for his arc to make sense, nor did she have to tell him that she was pregnant. Similarly, it was used to explain why Tyrion would believe her, but this could have happened for a number of different reasons.
When the announcement was first made, fans assumed that this would somehow be significant; perhaps a child would be born before Cersei was killed, and raised to be either an ally or enemy in the future. Perhaps she would die in childbirth. Perhaps her death while pregnant would serve as a motivator for Jaime to seek revenge for the death of his child. All kinds of options were open, but instead, the storyline went nowhere, and her pregnancy didn't seem to factor in to much at all, except for possibly Jaime's defection back to the Lannister side.
Cersei's Death Also Ruined Jaime's Arc
Speaking of which, Cersei's death also brought Jaime's arc to a spectacularly unfulfilling close. After seven seasons of character development, of seeing him learn to be a better person, turn away from Cersei, and fall for Brienne, fans were thrilled to see just how much he had changed from the arrogant blond who pushed a kid off a tower. Many hoped that he would turn out to be the valonqar and kill her, marking a total change in who he was.
Instead, Jaime inexplicably turned back to King's Landing, and died in a romantic scene with his sister, doing away with years of a carefully drawn story. It's not surprising that fans were furious that the two were simply crushed together, when both deserved more of an end than that. Not to mention the particularly unrealistic way that the two reconnected. Somehow, Jaime was able to get seemingly fatally stabbed through the gut, twice, and then climb his way into the Red Keep from the beach, find Cersei, climb halfway back down again, and comfort her as they died. More than anything, this felt like the show needed the Lannister twins dead before the finale, and didn't bother putting in the time to do their deaths justice.
Books Have Time To Get It Right
Time, of course, is the key here. In many more areas than just Cersei's death, the final season of Game of Thrones feels incredibly rushed - there's just not enough time to allow these characters arcs to play out in full. With two books left to come in A Song Of Ice And Fire, though, there's still plenty of time to pace these out so that everyone gets the attention that they deserve. Furthermore, Cersei will certainly not suffer the same disappointing fate on the page, because while the valonqar part of Maggy's prophecy was cut in the series, it's a much larger part of the books, and will presumably come to fruition in some shape or form.
Without time and episode constraints, George R. R. Martin can unspool Cersei's story in a way that ties up the loose ends of prophecy (and pregnancy, should that pop up in the books), and that hopefully gives her a little more of a chance to be cunning, not just to stand in the keep while her city burns, and then run away to be crushed. The Golden Company is also going to (presumably) have a bigger role to play, as will the many characters that the show cut out. At the very least, it's highly unlikely that a ton of bricks will be her downfall, and for that, book readers can be extremely grateful.