Here's the deal. Gabi's character, motivations, etc, in-universe make sense and fit into AOT's themes, so in that sense she's a "good" character. But what ultimately makes her bad is outside of the story: it's her effect on expectation and narrative momentum. Basically, she's not a bad character, but how Isayama implemented her character is terrible.
A good writer creates a narrative that inculcates certain expectations in the viewer, which can be described as the story's momentum, and then plays with/subverts that. A bad writer tries to play with/subvert the momentum but fails, chopping the momentum off at the knees or diverting it so hard or to such a strange place that all of the emotional investment and expectation from the viewer becomes unmoored and discombobulated.
Horror movies are the prime example of this working or not working. The primary focus of a horror movie is to play with the narrative momentum using "will they or won't they be killed" scenarios. If done well, it's an exciting twist; if not, you're left rolling your eyes thinking "So they did/didn't die? That's stupid." If you think of the antagonist from shin sekai yori, that was his whole character: we have the narrative momentum going, and he explicitly weasels his way into critical moments and shifts them or messes with them in a way that is disgusting and enraging. This allows you to properly hate the antagonist, so when he gets his just desserts in the end, you feel quite satisfied.
Gabi is a bad character because she does this same thing narratively, but is meant to be sympathetic. Gabi weasels her way into critical story moments that, vis a vis narrative momentum, she shouldn't be in, and then subverts or destroys that momentum. She kills Sasha, blows off Eren's head, and more, and in every story beat she's not really supposed to be there. She comes out of left field in critical moments and chops the momentum off at the knees. Generally, the only time this is a good thing to do as a writer is when you are trying to make that character hated -- because viewers will definitely react negatively to whatever or whoever broke the narrative momentum.
And therein lies the problem. She ruins the momentum, we react negatively, and yet the show still tries to persuade us to view gabi sympathetically. All of her reasons for being in the story -- to examine propaganda, psychological warfare, the generational cycle of hatred, a mirror to Eren if you want to go there, etc -- could have been explored without her destroying the narrative momentum in these critical moments. Or Isayama could have written in better reasons for her to be there, so she is now within the narrative momentum itself and not fucking with it from the outside.
Simply put: Gabi's a literal who, consistently weaseling her way into situations from left field and then does something damaging to the momentum. A prime example of this happening in another show would be Game of Thrones and Arya killing the night king. The show was highly praised for how well it had subverted expectation, but it completely dropped the ball in that moment by subverting too hard and too stupidly. Everyone hated that scene and rightly so, because it wasn't about the in-universe arguments, but the narrative momentum argument of her coming out of fucking nowhere and easily killing the night king after years of a momentum buildup to a showdown between the night king and jon snow.
Brayden Young
TLDR, shitkasa sucks
Blake Johnson
ok retard
William Gutierrez
It's bad when she's a mary sue
It's good when she's shown as a manifestation of marley's brainwash
Austin Sanders
Its just frustrating because she's an annoying bitch and it was obvious she was never going to meet a grisly end.
Jacob Gray
At least she saved more Eldians during the war than Eren ever did in his entire life.
Thomas Reyes
Can some user summarize the main points in two sentences or less? I literally cannot read this entire wall of text without suffering constant brain spasms desu
the problem is that logic and reason bend so that her story can continue
realistically there's no way she should have been able to zipline up the hook while carrying a rifle
James Johnson
Falco’s worst offense is turning into a bird at the most convenient time, but by that point there was so much wrong with the plot that that particular deus ex machina barely registered compared to how retarded every character was acting anyway.
Michael Morgan
He's the super good kid who has no hate and wants everyone to get along and immediately understands and emphasizes with the enemy. He's walking fanservice to appeal to the audience by having him be sympathetic to Paradise. Anyone on the other side showing that lack of malice towards Marley would have and has been crucified by the audience. He just learned that his best friends have been killed by Eren and the first thing he does in response is being apologetic and trying to defend him and tell Gabi she's wrong. Fucking imagine, your best friends just killed and you're siding with the killer a few minutes later, kek, what a fucking joke of characterization, all to please the audience, making you go "see? this kid is great, he gets it, he likes my side, he's good just like me and my favorite characters". Pathetic and revolting, way more unrealistic and idealistic behavior than anything Gabi related
Jason Long
An AOT character is badly written? Shocker.
Ian Howard
The problem with Gabi, and with the entire last arc, is that Isayama is biased and he threw gray morality out the window. The characters development is not natural at all. Isayama forces the "good " guys down everyone's throats, rather than leaving it up to the viewer to decide if they're right or not.
Aaron Allen
Pointless character whose only character trait is being in love with Femren. At least Gabi is supposed to represent the effects of brainwashing or whatever.
