We all know that the strawhatts will get new crewmembers, I think that in this arc, Robin, Usopp and Paulie will join the strawhatts, and Franky will dismantle merry and of Merry's wood he makes a new but more powerfull BattleFranky. Then after that I think thwy will only get one more crewmember, a female musican with, white or light blue hair, and her personality will remind of Tashigi, but she fight with a intstrument.
So I think it will be like this:
Goofy and funny guys:
Monkey D Luffy
Usopp
Tonytony Chopper
Serious and proud guys:
Roronoa Zoro
Sanji
Paulie
And the girls:
Nami
Nico Robin
And the musician girl
and then there is the franky ship.
And I can also do like this:
The strongest:
Monkey D Luffy
Roronoa Zoro
Nico Robin
The second strongest:
Sanji
Paulie
The musician girl
The weakest(but still strong):
Nami
Usopp
Choppa
Maybe you think that Choppa is stronger and deserves to be with Paulie and Sanji, but he's not so strong, he just got a really good ability to change forms and he can discover the weakness of the enemy, and this is all thx to the rumbleball he got, iwhtout the rumbleball he's not so strong, and one piece red,his combat data lies on a 2, just like Usopps I think… And now Usopp has improved greatly from the trip in skypea.
I must go now, so I cant post more theories and I hope there's not too much spelling and grammar wrongs.