Big Mom and Kaido saw the aftermath of Zoro's dodged attack, impressed but not shocked.
Big Mom's eyes were bulging with veins as this attack was happening and we got reaction shots from Kid flabbergasted at the insane power Luffy had. Kid didn't say "how did Zoro get such power in an instant" or something like that, did he? So no I wouldn't personally put it on the same level as Luffy's strongest attack to date, considering a King Kong gun is stronger than Hiryuu Kaen in terms of single attack damage already imo.
As for the blood from the slashes, if Oda doesn't draw that from a sword slash it looks like NO damage has been done, he recovered and fought back instantly, I wouldn't hype it anywhere near the level of gatling personally, but we'll have to agree to disagree.