He can, Kaido didn't even fall on the ground after Zolo's attack, that's the lowest level scar, DFless BB scarred Shanks's CoC/CoA Haki defense as well, which we don't know if Mihawk did, you simply say things with no proof. Mihawk couldn't scratch Jozu, Mihawk clashed equally with Vista, Vista can scar Kaido or not? He can't, but you still wank Mihawk.
I wank Mihawk because I'm sure that he will show CoC coating, advanced CoO & CoA like Zoro will have & sky split in the future as a former Rival of Shanks before his fight with Zoro.
Especially since ch. 1033 re-established the WSS title as a Kingly Ambition and Mihawk is the current WSS.
Nothing like that exists for Shiryu.
Idgaf about what you say Shiryu can or cannot do, show me panels of him blocking Hakai even momentarily or scarring Kaidou.
Even without that panel, the bare minimum is he has to show CoC coating, to even say he's on the same league as KoH Zoro.
If even Mihawk doesn't show that, then same applies to him.
If you think Shiryu's DF is just basic invisibility LMAO then you will be surprised I guarantee that. Oda gave island DF to Pizarro and strength DF to Burgess, and you think Shiryu is just a random invisibility LOL.
What? You think it's some Mythical Zoan or something?
It's simple, it's an Invisibility Fruit which is tough to track w/o whatever Powerup Zoro will need to track it.
Simply a matchup problem.