@Sugeeking:
Now that we're at it, Robby, what is this stuff about secondary characters having less unique design than main characters? This is not how One Piece works. I thought that much was obvious. Oda puts unique designs whenever he feels like. You don't tell me that Nami's design is more unique than half of the Big Mom crew's.
It's not just being unique. Because you can make any crazy weird shaped person for unique. Oda made one of the world leaders a guy with a big mustache and a sombrero with a cactus on it. And that stands out and is unique. But that's just general flavor.
It's the THOUGHT, the little details. The something that says Oda thought about an event that happened earlier in the character's life, or an accessory that has meaning to them or shows off their personality, that something that basically only they out of hundreds of characters possess, at the time of their introduction at the very least. An overall combination of traits that make them unique even among their own kind.
In Nami's case, she's the only orange haired character in the entire series pretty much. She has a tatoo with history on it, wears a weird compass on her wrist, always wears another bracelet there as well (from her sister), and at this point in the series has a giant floof of big hair, wields a bo staff, and now has a talking magic cloud. But most importantly, she was the first prominent female character in the series and was introduced in a standout distinctive way, in what, chapter 8? After being in the very first chapter color spread? And that by itself was enough at that point in time when story arcs were 5 chapters long and we'd met like a dozen named characters total. Her initial design probably wouldn't cut it as a crewmate if she showed up now for the first time, but her chapter 100 with the tatoo, compass, and bracelet would be something. Oda grew a lot as an artist in that first couple years. (And even Luffy the main character he's given a big X scar to in order to make him stand out more.)
Take Arlong for instance. He's got the crazy sawtooth nose. And that would be enough for a lot of creators. It's a standout unique feature that no one else in the series has had. But he also had the leather cap, the pronounced but thin lips, the bold patterened hawaiian shirt, a gold chain bracelet, two fluffy things at his ankles, two different tatoos, the spiky hair, the fin on his back, jagged teeth, the jagged blade. Everyone in his crew had the arlong tatoo, and we got context for the sun symbol later also shared by all of them (but not Nami!) He's even wearing rings on one hand, even though he webbed hands. But still, Compared to every other fishman in that arc he was completely distinct. Lots of details and thought and reiteration put into his design.
His main guys, Kuroobi, Chew, and Hachi also had some details to them and really stood out. Distinct mouth shapes, haircuts. Hachi had the extra arms and stickers, Karoobi the arm fins and twin pigtail and karate outfit, Chew had the blush on his cheeks and a necklace and a different tattoo from the others.. more detail, more thought, but still not as much as Arlon.
Compare all that to the other fismen, like these guys.
They get maybe an interesting detail apiece, a slightly different haircut or a weird jaw, but they're basically just wearing ordinary clothes and have no extra attention to detail, no backstory beyond the shared tatoo. Crab tatoo guy doesn't even look like a fishman. They are just background guys with no real effort put into them.
Or look at this concept oda did.
Those are guys were Oda just drew a humanized version of a kind of fish, got it in one go, and moved out without much change or modification or any further thought. Some of those made it to the story, some didn't, and you can see Chew before he was further refined. (There's also early sketches of Hachi where he was a girl.)
You look to any of the supernovas, warlords, strawhats, they're all brimming with the extra details and thoughts put into making them unique. If you comb through the scope of the series you can find a trait shared here or there, but if you put them in a room of other characters of equal standing, you can still tell they're important.