are there any ship positions that still need to be filled?

I think all the ship position are already filled, I guess you ask this for the futures nakama would be part of the strawhat crew but it doesn't matters, luffy doesn't choose his nakama because of their strength or their skills. For example Robin doesn't play any role at the ship or in Chopper's case Luffy invited him to cadastrar-se the crew without knowing about his medical abilities.
At the beginning of the story Luffy said he wanted around 10 nakama to sail the Grand Line, so surely only one person will cadastrar-se the crew. Some persons say that it would be boa, jiboia Hancock and others say that Luffy and the rest will meet him/her in the New World.
I'd like it will be boa, jiboia Hancock 'cos she's so funny XD

:)

I like the crew the way it is right now, so if somebody's gonna join, they had better be awesome, funny and strong. I don't want it to be just anybody. Or anybody that they've met already (unless it's Bon-chan, that would be awesome!!!) And I especially don't want Hancock to join. Don't get me wrong, I amor her character and I definitely want to see mais of her but it would just cause too many problems.
1. What would happen to the Kuja Pirates??? If Hancock joins the crew, they'll either have to disband or cadastrar-se Luffy's crew as well. And I don't want either. Me, being a girl, totally amor the awesome butt kicking-ness of an all girl's pirate crew, and I don't want them to disband. I also don't want them to cadastrar-se Luffy's crew. I've always loved the irony of the future Pirate King's crew being petite. Just a little group of misfits who don't really belong anywhere but there. Plus, it's only Hancock's status as a Warlord that protect Kuja Island. If she were to cadastrar-se Luffy's crew, she would fired and the Island would be attacked!!! Think about it, he's the son of the world's worst criminal, how do you think the World Govt. is going react if she joins the crew? Plus, if he becomes Pirate King, that's even worse for the Kujas. With their affiliation with the Pirate King, they would immediately be eradicated. Maybe in a buster call.
2. She loves Luffy. I've always loved the fact that One Piece is a mangá where adventure is main priority, not amor like all other Mangas. Besides the odd pervert (i.e. Sanji) amor isn't really that important in One Piece And tI want it to stay that way. But if we have a Straw Hat who is only focused on professing her amor for Luffy, that would totally kill it for me.
So, all in all, I want any new Straw Hats to be Funny, Awesome and strong. As well as it being someone new and not someone that we've already met (Unless it's Bon-chan! <3)(especailly not HAncock.)