I can see that happening however, many fans will not be satisfied in Oda off screensthe battle.
I believe a couple of the SH will only accomplish their dreams after Luffy becomes pk.
Brooke's dream of meeting Laboon can only happen after Luffy becomes pk
Nami's goal of drawing a world map can only happen after Luffy becomes pk. Mind you, at the moment, the SH have barely explored the world and by the time Luffy becomes pk, it would still be the same. Look at paradise, the supernovas used different routes to get to a body, meaning that there are multiple areas the SH have not gone to which means they will need to visit them for Namito draw the world map.
Chopper's dream of curing all diseases. He can only achieve this by traveling the world and curing the people. Only achievable after Luffy becomes pk.
Franky's dream of creating a ship that can sail the entire world. Only achievable after Luffy becomes pk.
So it is not like they will be doing nothing after Lufy becomes pk. They will continue sailing the world, will be the strongest crew in the world thus will have the freedom to sail everywhere and accomplish the dream ofthe different SH that require them to sail the entire world