wait what do you mean about the personality usually found in sanji's opponents if you mean goofinesss remember sanjis opponents in the arlong pirates) though I find it annoying that some people act like goofiness is relevant to them being strong in a world like one piece
They have a clownish personality and often tend to argue with Sanji more than fight properly...
Kuzan ain't like that. You have a point with Kuroobi tho.
It is the strongest, most competent and most complex character in the BB crew. His design and DF rock. It is the dream match-up for any character bar Nika.
It is a particular good match-up with Sanji due to opposite temperatures.
It would be a match of Sanji heating up before Kuzan's cold overwhelms him.
Also, a strong kicker vs a strong puncher on top of temperature parallel.
Shiryu will always be Zoro's dream match-up.
I would pick him over Zoro clapping Kuzan and BB together. At least if he delivers what I hope he will.
And regarding Law's haki against Kuzan, it will not help.
The chopping up into piece doesn't work on someone who has formless regenerative body like logias.
Attack with long charging time like Puncture Wille, even if Kuzan doesn't off him 10 times before its charged, doesn't work on logia body.
He will morph away from the stab effortlessly. The same applies to Shock Wille.
I doubt you can hakify Gamma Knife, Counter Shock might work but that didn't bother even Vergo...
And then, on top of majority of DF abilities being ineffective, there is a huge gap in CQC...
In short, Law ain't beating Kuzan. Sanji's chances are far better.