M3 cover each other in terms of every side.
Oda want to show some valuable things people with his child.
Zoro was born as a fighter. Like Luffy, since 7 8 years old, he is making training. Only concentration is that. Because , zoro want to show the path that going to victory can not be actualized training , hard way.
Sanji was seen as a failure . He escaped. His special ability has never been fight. Even though he does not care this , he is very strong . But cannot be than zoro. Because , odas message is very clear.
Sanji want to show any food should not be wasted .
Briefly, Luffy want to show nobody success themselves . Everybody needs nakama and everybody needs help to reach purpose.
That is way, after PS , we have seen gorgeous arc.
But , oda lost balance.
Before ps , zoros path is kinda challenging and we felt this to become wss. Mr1 , against Kuma, against hashi against Kaku . Right now, zoro achieved everything easily .
Before ps, sanjis pervert side was not written much . And we saw him very cool moments also.
Yes, still good. But balance lost. Cuz , if you check laws moment , oda prefer to give some skills to law from the sanji.
Speak of Luffy , we read so much Luffy. And mostly he hang out side characters not crew. And dynamics of SH balance lost.
End of the day, oda want to give message . All of them are his child (core member)