And some of you people said that my talking about Sanji vs Vergo was boring subject -,- God..
As for last revelation- what Bellamy said about Lyffys haki- I think that having CoO on decent level makes you capable of estimating other people haki strength.
Blackbeard before time skip commented on Luffys haki being stronger than first time they met. This time Bellamy was amazed by Luffys haki.
Soooo as for Vergo-Sanji thing it has gotten extra depth thanks to words from Bellamy
Sanji was confirmed CoO user and when he started to fight Vergo Im sure that he was able estimate how strong Vergos haki is. So he thought that he had chance to win or at least fight can end up without any really serious injuries. So after that I do think that what failed Sanji back then in their fight was mostly his body http://mangahelpers.com/t/cnet128/releases/35559 as it was said that Sanjis body after being blown up by Cesars attack was an awful mess. Even with his haki Vergo wasnt able to do more damage- crack more of Sanji bones after fibula gotten cracked, just after it we saw those lines- electricity like when Vergo and Sanji exchanged kicks, in many other occasions that haki was most probably "equipped" we saw those electricity-like lines so what I think is that even with one leg being fully healthy Sanji was able to stop Vergo from overwhelming him/making him suffer more injuries so Sanjis haki/hardness must be on very close to Vergos level- no overpowering like some people said.