you can't really exclude, luffy (OP), or naruto and suske (Naruto)yeah yeah, luffy is the only exception as said many times in this thread
And still blackbeard used tremor tremor ability with a lethal way. That's my point.
Good answer.
why? they are the main characters and obviously the author will follow them, and hence represent their respective worlds, for example from the little bit we say from neji vs lee's story genius born in elite family vs hard working dropout with no family same concept can be seen naruto vs suske
even if you look at other groups..u got the genius shikamaru with a hard workin choji so the concept is the same.
now for one piece, since his the main character obviously we'll see more of him, and if he didn have devil fruit he would have something else...look at zoro his constantly training in his art..same goes for all the other crew members. also none of the characters that magically learn to use the devil fruit abilities, take the cp9 example...the giraffe guy. even though he was specially trained he was struggling with his abilities even though its the simplest to master(zoan)..the wolf was even laughing at him....and it showed the more familiar he got with it, the stronger he got