Well theres nothing that said "haki is not a separate fighting style" , while Vergo explicitly separate himself as a haki user from him being a weapon user.
Based on your shit sites translation, yes. Not based on official:
Anyway, if this was your argument then it's refuted. There's nothing like "haki user" in canon as a combat-style. Majority of of characters, including Mihawk, Shanks, and even as low as likes of Helmeppo , are users of haki. It's nothing separate.
Rest of my points from previous post stands. Haki isn't separate from swordsmanship. Hell, swordsmanship is more about haki than it is about anything else as far as we're shown in narrative.
Mihawk's overall portrayal puts him above Shanks, not in any particular thing or that.