Holy shit. From the man himself.
Wings of the Pirate King.
Zoro is the sword and Sanji is the shield,
Scopper Gaban being an absolute unit,
Zoro only properly learning to control his Haoshoku in the same arc Sanji acquires his, etc.
Narrative is generally more important than feats, and the narrative Oda is pushing is that the wings of the Pirate King are comparable in power.
I do not like it, and for a decade I believed otherwise, but it is what it is.
I was simply wrong (or Oda changed his mind), but regardless.
Current narrative is Zoro ~ Sanji.