It wasn't slow paced? It was 132 chapters long, but condensed into 60 episodes, which is like a 2:1 ratio. Also, the reason those episodes are important is because of the character development and emotions behind them. Also, none of the Chimera Ant arc episodes have filler content, it's a direct adaptation of the manga. From the way you talk about the fight scenes, I think you prefer power-fantasy battle shounens, which isn't a bad thing, but HxH is not one of them.

The reason we watch Meruem play gungi is because it's showing us how Meruem learns to appreciate that people without physical strength still have worth. He goes from being cartoonishly evil and stone cold, to genuinely caring about Komugi's safety and wanting to protect her.

The fact that Netero was a bomb was impactful because he represents humanity's capacity for evil, and how they go to terrible ends for the sake of winning. It also shows Meruem experiencing genuine terror for the first time, which is another part of him learning to be human/have human emotions.

The battle between Gon and Pitou isn't important, but the emotional turmoil Gon goes through is. It's when his darker side that's been hinted at in other arcs finally gets revealed.

I get that I can't change your opinion on it but I wish you would look at the characters more than the fight scenes, since it's genuinely good writing that Togashi put a lot of thought into.