Nah Lucci couldn't hurt Luffy with regular attacks. He admitted to it.I think the Haki introduction was done pretty well crocodile isn't a hand to hand fighter he fights using his logia based devil fruit so he couldn't show his Haki. I think characters have been using Haki for longer then we knew like rob lucci now that I think about it luffy is a robber man but has been hit and hurt by punches even before the Haki was given a name. Without knowing it the enemies of luffy have been using Haki like lucci. Even zoro vs Mr.1 he dodged all the falling rubble while half dead simply stating he knew where the boulders wouldn't fall. Just goes to show the genius of Oda.
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Zoro's observation haki moment could be legit though. Yea.
Aside from that Haki was horribly executed. One of the biggest cluster****s from Oda.