Execution means how you actually tie your themes into the story. How you write the actual story around that theme, how all the events in an arc work together, how you develop your characters based on that theme and how the finale and conclusion of the arc works.
Togashi's chimera ant arc is an almost perfect arc in every aspect (themes, execution and character development). The only OP saga that comes close to that is the Water7/Enies Lobby saga.
you sure re read the arc please then it doesnt work together its a typically one dimensional shounen story most of the story can be skipped too much talking the revenge for Kite is annoying the MC has no real purpose then revenge he takes on this task due to take revenge which character development all characters got just stronger nothing
In short of the arc we have awakened monsters who build up followers and "eat" people for gaining strength than an association who opposes that its typical power ranger its just looks to us good because of the music played and the whole stretched dialogue
For example Dressrosa you have a trickery gangster who tricks the people into worshipping him and then he uses his devasting might to crush the good people and gets applauded to it he uses his brain rather than just pure strength
creates a country where the strong live and weak die uses his connection (again brain) to build a network of black-market trading and provide the world with all the needs they have
In midst of this, the MC comes a challenge him due to his own selfish desire yet starts to work with the citizens yet the villan makes the citizens against the good people again this time due to his power and psycho games
And despite the people betray the good guys they keep on fighting and win in the end
Plus this event effects the whole world
Kaido an emperor got caught off guard
Kingdoms who were provided by it lose power or any means to continue the war they fight
Also it connects to Zou Jack incident that again helped them to gain more allies for wano and Zou is connected to WCI
The play of ph-dressrosa and wano is perfect working its scale is just much much much bigger than the puny chimera ant arc
I admit due to the scale people sometimes cant see how fantastic OP really is but also the anime is an factor while people downgrade
Be it character, be it execution, be it the story lines overlapping perfectly or themes in every aspect HXH loses
The difference is the effort the mangaka puts in Togashi is an asshole he has the mainstream idea that his story is for smart people and thus hxh seems like apart from other shounen mangas but if you read it again you see stretching dialouges , repeating the most common and simple information in a long stretch way
So we cant really compare an ant to an giant
One Piece is globally you have so many characters so much lay out so much stories if OP ends Oda could still write side stories for 100 years it has so much potential
Berserk is excellent but its 1D in his own feudal time its perfect even more exciting than the OP
For JoJo we both have mutal consens
But for HxH I cant accept it I also read it everywhere its just headcanon to assume HxH>OP when OP is in a different universe