Ehhh. Naruto has an expansive character list but Team 7 gets most of the spotlight. Minor characters leave more of an impression on me in One Piece, just cause they look strange or have a colorful personality.
Honestly I think the names of the three main series say it all. One Piece is named after a mythical treasure, and in a goofy way it's about the closest tv series to a long, fun, and totally rad adventure of Dungeons & Dragons. The minor characters are one dimensional and come and go, the plots are drawn out and completely exploitative, but I don't give a fuck. Whenever Luffy saves his Nakama and punches the bad guy in the face it is so cathartic.
Naruto is named after the main character, and is a gripping character piece bordering on absurdist existentialism. If you don't like the main characters (once again gotta bring up people treating characters as acquaintances and not tools), you won't like the series as much. Minor characters are also meticulously crafted and plotted and if they weren't so you wouldn't want to see so much more of them. Granted this all has the side effect of if the story ever gets hopelessly stupid and convoluted it might just collapse in on itself where One Piece wouldn't, but I mean, like, that would never happen right? :(
And Bleach is named after nothing because it's meaningless and "edgy".