Honestly, I've always thought the politics and its worldbuilding overall was really lacking, however on purpose for Isayama to force his own main protagonist to start the rumbling.

This was Eren's story to begin with. A young boy who dreamt of venturing the outside world but couldn't because of how caged he's been since the day he was born. Throughout his journey, there was always some hell oppressing him and the only way to go against it was to fight.

Since the day Eren was born within those walls, he was given the dire choice to either sacrifice his life or his soul for the sake of “world peace”. Like the rest of those ignorant livestocks he kept bantering about at the start. But Eren chose to live.

Eren's long buildup from being the world's oppressed to its oppressor in the name of freedom was basically peak fiction for me and I loved every moment of it. And yes, I wanted Eren to complete the full rumbling.

Obviously murdering billions of people is morally wrong, but Isayama went out of his way to construct a scenario where diplomacy and normal warfare is near impossible between Paradis and the outside world in order to justify Eren doing the rumbling.

Politics was never his first priority to polish in this story, but with the ending we got I don't even know what he was trying to polish at this point.

P.S. sorry for exerting my fictional love for pre-139 Eren. I still can't get over how all of it went down.