And why is it not a great arc?
Anybody ever take the time to realize the most revered arcs in the series are arcs in which a main character is in direct peril? Marineford and CP9 are undoubtedly liked the most but it surprises me how many people don't get that you simply can't repeat this type of arc again.
So I guess people want Oda to conveniently put these strawhats who trained for 2 years in pathetic turmoil?
Yes we want that, tell you what it's a fucking good thing to be as sadistic as possible to your own protagonist.
And now tell you another thing struggle can come in different forms it doesn't have to be an enemy that seems like he could squish the strawhats with his little finger.
The answer how all these fights could have been way more engaging is more build up and smart handicaps. But that would have meant this arc would be even longer than it is now which poses a different question: Would that be really more desirable? Oda's doesn't think so apparent by the way this arc has been paced (very fast).
Saying that this arc has been shit is in my opinion way overboard, but it definitely isn't as enjoyable as it could be, but if people would look at the story structure (especially how the time skip affected it) I don't think many would find a way to make this arc better without stretching it into oblivion.
Also saying HxH sucks as a defense response is pathetic, even if you don't like something you should acknowledge the things it does, and bad storytelling is surely not one of them.