Onigashima hasn't been copy paste of anything
It's the most unique fucking arc in OP so far.
Wings implies importance, yes, not equality. The clear-cut narrative is the Kuma situation where Sanji and Zoro are shown as most important, but Zoro a step above. Quit denying canonical stuff for the sake of factifying your interpretation. It's just like how PK's two hands would be important- but not necessarily equal.
VC straight up calls Zoro as one who acts like Vice-Captain for Luffy and crew, idk what's there to add.
And story has unfolded for 1000+ chapters so far; and Zoro has always been narratively above in power, importance, or anything in-between. That doesn't mean Sanji is shit- he's very strong and incredibly important, but his fans will be a lot happier if they just stop trying to put him on exact same pedestal at Zoro with everything.