Is this a cop out? There is a chance that Oda wants to make Ashura an exclusively Zoro ability for no other reason than Mihawk has to lose to it.
And for Mihawk to lose to it, he must have no idea what it is.
So this will be a Haki ability only Zoro can do. Ever. Across the entire verse, Joyboy to Ryuma to EoS Luffy, no other Haki user will ever use “Haki constructs” besides Zoro specifically so that Mihawk has no idea what to do about it and loses to it.
And for Mihawk to lose to it, he must have no idea what it is.
So this will be a Haki ability only Zoro can do. Ever. Across the entire verse, Joyboy to Ryuma to EoS Luffy, no other Haki user will ever use “Haki constructs” besides Zoro specifically so that Mihawk has no idea what to do about it and loses to it.