Luffy is a great protagonist within the confines of the OP story with the themes Oda wants to express.
It´s just that people think he is some Shounen clone because he has some superficial characteristics that have been featured before, most prominently in Dragonball.
I have read 500 chapters of Bleach and could not say who Ichigo really is, he is used more often as a plot device than an actual character.
You mean the obnoxious two brothers? Meh
Luffy might look like a regular shonen character and he is.But there's more to him. Very early in the story he admitted that he needs help to achieve his dreams. He continuously relies on others explaining his care free attitude towards daily activities and non life threats. He gets serious in fights, he gets serious when he has to lead and as of last week we know why he knows people so well after a quick chat.
You don't understand ichigo. He's s complex character. Just because you didn't get it doesn't mean he's badly written.
Btw, by your standard, who are this generic shonen characters