Yeah, the only reason I'd suggest King and Queen as well is due to their names literally being King and Queen, and their ranks being first commander/vice captain and second commander, as well as them acting similarly to Zoro and Sanji/fighting against them. They were also portrayed as the two pillars holding up the Beast Pirates on the live floor now that I think about it...
Yea they do check boxes at face value but when you dig a but deeper Zoro and Sanji's chemistry is unique too (which you can argue is native to them) the fact that there is no official VC in the crew puts their chemistry on the spotlight , and the fact that what "wings of the PK" symbolically implies
Kaido can rely on King more than on Queen definitely for instance he took him to the confrontation with Shanks
Wings symbolically are equally reliable Luffy did show that while trusting the crew to Zoro while he went on to get Sanji
which brings us to another figurative connotation of the label /title "wings".. without either of them he can't soar AT ALL.
while on the other hand Kaido recruits folks and accepts challenges from them to compete for an aggrandized position.. so for instance if Queen looses to a new recruit wouldn't that mean that to Kaido Queen is just inferior in rank and replaceable .. meanwhile Oda had Luffy exclaim that sanji is indispensable given the context ofc and oda himself emphasizes their importance in the SBS.
last but not least like aforementioned every crew has a VC but SHP doesn't have an official one.. given VC is the 2nd most reliable and broadmind in the crew.. in this case wings make it 2 leading figure that are equally as reliable as a secondary to tertiary opinion.. take for example Water 7
sanji and zoro were the only one's who dealt Luffy when it came to decisions he was about to make and the one he made.
Sanji stops Luffy from saying something he'd regret it letting ussop leave on his own will.
Zoro reminds Luffy his burden and the crew's captain and what it means for his decisions to waver.
Sanji and Zoro even have a moment where they get on each other's throats in Alabasta coz Zoro's anxiety over Luffy possibly losing against Crocodile.. Sanji taunts him for pondering ober such a possibility
so yea SHP are a pretty unique bunch.
