I agree that Law is a swordsman. However, what i don't agree with is that Law will be weaker than Zoro by default, since he is also a Devil Fruit User and Haki User, thus his overall powerlevel can't be limited by solely being under WSS. Thus currently, and also when Zoro become WSS, Law will be a weaker swordsman that is stronger in a fight overall mainly due to his DF powers, compared to Zoro.
This is TLDR version of my opinion since the start.