Ya and it looked like it didn't bother him at all, no reaction at all.. No urgh, no cough no gasp, no nothing..
He did outspeed and outmaneuvered Vergo but not casually, he was pretty serious using Diable Jambe and named attack Flange Strike..
Unless there is an inconsistency with previous events, i will go with Sanji got stronger from Punk Hazard to Wano..
That would be his ribs or the upper body because Sanji said '' again '' referring to his fight against Kuroobi where he broke several bones on his thorax due to the water pressure sudden gap.. I would agree with broken bones being inconsequential, but Sanji's legs are way harder than other parts of his body, its his main weapon and pride as a cook fighter.. That's why they were shown breaking on panel, as it is a big deal, its similar to Zoro's swords breaking or getting damaged, a dent in Wado Ichimonji or something..
Plus Vergo didn't user hardening versus Sanji, though he did for Tashigi..