Bruh.
> He detects where his opponent is going.
> Changes direction at that speed based off of that.
Fire cutting is a situational tool like Sky walk. Not a "powerup".
Luffy needed FS & G4 to surpass YC1, G4 put him in that conversation.
Zoro needed Enma and his end of the arc powerup to surpass YC1.
Sanji needs Raidsuit and this exoskeleton to surpass YC2.
Which doesn't require FS against non FS opponents, just basic CoO. He could adjust culverin and outmaneuveur Doflamingo without FS, jet culverin just moves faster, the mechanics are the same; if your attack moves faster than your opponent and your perception is equal to your opponent then your attack will most likely hit.
Sky walk is a power up too, but was a TS power up for Sanji not an
arc specific power up to enable him to do specific counters to Kaido and King.
Luffy had G4 from the TS, yes he needed FS to overcome a FS user, he probably wouldn't need it to compete against the other YC1s.
King and Queen seem nearly identical in portrayal, whether it be bounty, intrapersonal contact, portrayal within crew, Zoro's comments, Marco's comments etc.