Btw, i'm guessing right now but...
I think that after this arc. Luffy will either get a new member or he'll know how to control and master 'Haki' . And, probably, he'll teach it to his crew... or maybe his other crew members will know about it in their own mini-arcs
But those are just guesses... now I wonder how they'll take back their Ship. It's possible that when they meet up again, the ship will be long gone.