Are you seriously against a Mink joining because there's already a humanoid animal member within the crew?
Pedro and Chopper look nothing alike. Their only common trait is the fur.
I'm against him more because of the complete and total lack of any reason or indication of him being a crewmate to be.
But the guy's post specifically mentions he wants "a Mink to join". Meaning he is in fact basing some of his desire on a feeling that a Mink should join. And if you're basing it partly on that? Yeah, we basically have one already.
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@.access:
The problem is when he had the chance to redesign the SH during the time-skip and he actually made Robin look (ncredibly) generic instead of more unique.
Oda's female drawing has degraded over time for whatever reason. It's not Robin specific. She was losing her uniqueness already during the pre-skip anyway.
EDIT: And when a new character appears and people say "yes, the design is new and all, but you can tell by looking at it that Oda didn't spent a lot of time thinking about this design"… well, that's exactly how I feel about Jinbe. Jinbe may not look like other characters, but his character design is not really outstanding. He is cool and all, but that's all, it's a good fishman design just like any other named fishman/merfolk (Neptune, the princes, Hody, even Hody goons...).
Your whole argument is super confused.
Zoro and Nami and so forth are part of the more normal looking bedrock from East Blue and narrative earlyness.
Jimbei doesn't fit the "Chopper/Brooke/Franky" category of Grand Line random people that you're thinking of anyway, his unique factor is he's a Shichibukai. He's the former boss character. Robin's uniqueness wasn't character design either, she has a very unique role in the story.
Are you thinking any of this supports generic tertiary characters like 90% of the Minks? lol