This isn't really comparable at all. This fight was more similar to the King fight, where Zoro couldn't do anything until a specific power-up. Give both Daz and Zoro a senzu bean right after that moment and Zoro one-shots. He took massive damage up until the power-up, but nothing bone breaking like against the joint attack by Kaido/BM, and being able to cut steel is somewhat of a tangent to his battle condition, anyways.
Why use this example, lol? It was quite obviously made a huge point that the hit he took for Vegeta heavily nerfed him, requiring extreme willpower to win the beam clash. Otherwise Gohan was generally stronger than Cell.
To be clear, the Asura slash against Kaido was his strongest attack up until that point and him reaching a new level and is in-line with shonen tropes. But the general argument is that had he done it in a context where he didn't literally have a shattered body it would have been more potent. That's also a shonen trope. A character doing something crazy but still failing due to X circumstances and throwing out a lingering "what if". I don't think that's disagreeable.