I don't think I ever have actually said Zoro's Will Power is greater than Luffy's rather equal.
But both Luffy and Zoro's will power, desire to be better, pursuit of ambition is grander than any other character in One piece be it Gol D Roger, Xebec, Ryuma, Kong, or even Imu.
Hence why
@Jo_Ndule making Katakuri Zoro comparison is disrespectful.
Saying Katakuri has greater aura than Zoro is as insulting to Zoro as me saying Katakuri is comparable to Horse shit is insulting to Katakuri.
Saying Katakuri is grander than EoS Zoro is like saying turd is grander than Katakuri.