No. I think you are wrong because of the Advanced Haki concept. Advanced CoA is needed at least for someone like Kaido to penetrate his scales with cuts or in'n'out damage ( internal destruction ) for brawlers and etc...
Kaido has no scales in base.
What Adv CoA allowed Luffy was to focus much more the power in a single point (Barrier Haki) and with the 2nd lvl of AdvCoA (Internal Haki), he was able to put his Haki inside Kaido's skin (or scales when in Dragon form) and destroy this external defence from within.
A brawler doesnt need to destroy the external defence to deal damage as in the same way a vest won't protect you against the blunt impact of bullets, it only allows the bullets to not penetrate your skin, but it barely protects you from the impact of it (depend on the width).
Luffy not dealing visible wounds to Kaido prior to Adv Haki is irrelevant. He did damage but we don't know how much, which is anyway irrelevant since it was a YC1+ vs a Yonko.