This is the point where you keep making random distinctions that no longer exist thanks to Xebec. Where has it ever been stated that Mihawk is the world's strongest (cutting) swordsman lool, or that shockwave sword attacks are any less impressive than cutting sword attacks?
Mihawk is the pinnacle of swordsmanship. No one cares about whether the attack cuts, pushes, destroys from the inside — literally nobody gives a toss; as long as it is considered swordsmanship, Mihawk represents the pinnacle alive. Amongst the characters alive, swordsmanship does not get stronger than what Mihawk is able to produce. It's seriously that simple. Shanks can have stronger CoC if he wants that's cool, but all we know is that the sum of all parts that makes up swordsmanship is greater with Mihawk than it is with Shanks. Period.