Its true, that's literally the peak of battle shonen and I feel bad for the people that don't like it
It's very different from the rest of the manga and hasn't impressed me so far. I've only read up to like... vol 24 or something though as that's where the english release stopped last time I re-read it.
Kyoto / Shishio arc from Rurouni Kenshin, the Twelve Houses from Saint Seiya, the entire Slam Dunk run, Dark Tournament from Yu Yu Hakusho and the Piccolo / Saiyan / Freeza combo from Dragon Ball still stand above everything else IMHO.
I am surprised at the quantity of people choosing One Piece or even Hunter X Hunter over any one those legends; I suppose this is related to a generational change in the mainstream manga / anime consumers´ demographics.
As people already mentioned, not really a generational change at all. I have the same amount of nostalgia for some of your examples as I do for HxH and One Piece. While all of your examples are absolutely good (I've not read twelve houses tho) I don't think they stand above HxH or One Piece at all, some are on par for sure, some aren't (I disagree with you on Kenshin and Yuyu Hakusho).
I'm still a bit baffled by the love Yuyu Hakusho gets here, it's good but not THAT good