Do
Jinbei- simply because he's been asked to join.
Not
Anyone else
If we add a female character, given Oda's God awful track record she just becomes another stack of titted sticks that serves 90% fan service and 10% other stuff.
Honestly at this point I'd prefer Oda to focus and further develop the people he has.
So far his ability to balance development with 9 protagonists has been poor to say the least. Why bother adding another two or three when what we've got already gets poorly developed.
Zoro is virtually nothing more than a guy who says nothing until a fight. Then snaps a cheesy as hell one liner and shots on his enemy.
Sanji has been stuck either womanizing or running into virtually the worst situations possible match ups.
Nami can't find a shirt to save her life. At least she's one of the only SH consistently developing post skip.
Robin: Ussop has probably done more in two arcs than she's done the entire story. Oh and she can't seem to find A pair of pants.
Franky: only really shined during PH and a moment on Dressrosa.
Chopper: other than Punk Hazard Chopper hasn't done much.
Brook: Has done nothing much.
The SH's hardly interact like they used to. Zoro virtually only interacts with is Luffy...and that was to tell him to get serious. Well and his bickering with Sanji. Remember when he'd constantly get bosses around by Nami and was the manly man of Chopper's inspiration?
Quality is better than quantity. I'd prefer we stick with what we have and better develops them and have them interact with each other forming unique bonds than to watch a couple get solid development while the rest look like clowns.
Before I say what I am gonna say please please
PLEASE know that i do not disagree with your opininon or think its wrong i just do not share it to be my own.
Nami/Robin dressing differently than she used to is because the art style is different than it used to be and even then we had fanservice. In a shonen manga its to be expected.
And Sanji has not only shown more development (all be it in a wrong direction) first off he showed a side of him never seen before with kinemon and it was an intense responsiblity to follow through with things. Meets a guy and saves his life but will go out of his way to make sure he is
110% after that. And even with Viola as much as he is a pervert this arc showed he genuinely cares about women even enough to not lie to them ever.
Sanji has went from perverted bad ass to warm hearted yet stoic Cook in a matter of 3 arcs.
Fanky has just been upping his manliness and Zoro hasn't been sleeping more or less he has been sleeping the same remember when he slept through the entire trip to alabasta and then only got up to fight. Plus even in 2 seconds of dialog with his line to pika he shown ambition to not only beat Mihawk but to be recognized and not walk in luffy's shadow.
Chopper has shown his limits healing the kids before Law walked in. He has shown his bravery and show that he still holds his intesnse need for someone to protect him exclaiming that aslong as sanji is on the boat with them they should be safe. YET still fought with out heasitation in the fight agaist crazy toy lady. He is coping with his fear better than before.
Usops is the man.
And for brook i agree completely but how can you develop an 80 + year old man who is already who he is gonna be.