Icebrood was where Anet's shitty story practices really began to shine; the expansion focuses on dealing with a Charr civil war, with two in particular - a Charr commander known as Bangar Ruinbringer, and Ryland Brimstone, the child of Rytlock, leading something of a civil war against the High Legions. The two had different motives; Bangar was apparently looking to secure an Elder Dragon of their own, as he had apparently been growing suspicious/jealous of the PC's own Elder Dragon ally, Aurene. Meanwhile, Ryland... I legit can't figure out, the kid just seemed like an idiot.
It seemed like a solid set-up, with the story making it clear that both sides have some legit grievances; however, it all very quickly went to complete hell shortly afterwards. Bangar was made out to be an insane and violent racist and fascist who would happily destroy everything for power, turning massive amounts of Charr into minions for the Elder Dragon Jormag, (who was very explicitly made out to be non-binary for some reason, which the characters went well out of their way to respect because apparently pronouns take priority over destroying the fucking planet); these mutated Charr became known as the Frost Legion. Meanwhile, longtime fan-favorite reasonable authority figure Smodur the Unflinching went from a calm, experienced commander to an insane psychopath who tried to cause a second Searing, apparently to "gain an edge" against the Frost Legion; he was swiftly killed and replaced by some "strong, independent wamen" Charr that I legit can't remember the name of right now.
From there, the plot just went further downhill; the story made every male character out to be a braindead idiot, every female character into the same "strong and brave" stereotype, the villains began sabotaging their own plans for whatever reason - i.e., Jormag putting the idiotic Ryland in charge of the Frost Legion, while more-or-less handicapping and sidelining the tactically-intelligent Bangar, letting him get captured in the process - and some outright idiotic story changes that leave a few too many plot holes, like the entire Flame Legion collectively pulling a heel-face turn and joining up with the High Legions, with said Flame Legion leader constantly praising and deferring to the aforementioned "strong and brave wamen", and one of our allies - I think it was Braham? Been a while since I checked, exactly - becoming another Elder Dragon's (Primordius) minion in an attempt to fight Ryland on equal ground.
In the end, the story ended about as well as you'd expect; Ryland and the Frost Legion all dies after Ryland continues being an idiot, both Jormag and Primordius getting destroyed - despite an earlier plotline making it very, very clear that any more Elder Dragons dying would destroy the entire planet, though our little dragon buddy Aurene is apparently able to absorb it without problems, so I guess it's no longer an issue? - Bangar is imprisoned and either dies or is executed, and the entire cast starts celebrating that all of the more "violent racist and fascist Charr are all dead". Also, the death of Jormag was what killed the Frost Legion, as the death of the Elder Dragon was supposed to kill whoever was mutated by them... but for whatever reason, the allied character that became Primorius's minion didn't for whatever reason. Oh, and the devs themselves went out of their way to cater more to the glowies, and made it very clear that the Frost Legion was supposed to be a stand-in for the American right.
Also, on a more minor note, Icebrood more-or-less canonized the Human PC as the canon one; massive chunks of the expansion were very obviously written from the assumption that you were a human character, leaving the potential plotpoints of Asura, Norn, and ESPECIALLY Charr players in the dirt. As a Charr player myself, I was not pleased.