When the crew has accomplished most of their dream and is getting ready for the final war, I have this image in my head each Straw Hat leading an army warriors around the world to do battle, bring others to their cause, etc.
Brook takes Laboon(and somehow his family) and rides like boss on Mountain Whales preaching the word of D.
Sanj leads a massive group of Okamas and reformed marines.
Nami flys around the world on a little cloud like Goku leading a sky island full of warriors.
Usopp leads the giants and little people commanding like the god he is!
Jinbe takes all able bodied Fish Man Warriors and a fleet of whale sharks.
Chopper, Robin and Zoro are a little harder for me to imagine. Well Chopper mostly but I can see Chopper getting major focus on some animal themed island or somewhere where his doctor skills put him on a pedestal nation wide. Zoro will probably have some major Wano development coming and Revolutionaries for Robin? I don't know.