That's not really an argument I accept, any more than Koutarou's nuke putting him out of commission for a while (which unless I'm misremembering, didn't, because he was out training with it in the dunes a while later). It's not really about the power level, I'm quickly discarding that. But I'll cover my point with the next snippet.
Katsuo also would never fight Shinji, so this is kind of irrelevant. The point I argue is that Asura more or less matches his corner of the group. The same with the barriers. So it was kind of offputting and annoying when, after Katsuo was trying and flailing, Shinji suddenly came out of nowhere with his shikigami power boost and did what he couldn't. Could he be weaker? Sure, fine. I'm not saying Katsuo should handle everything on his own. It just felt in that instance that Katsuo was being outmatched in his part of the plan, and his niche of the team, which is the bruiser. And that is kind of what he's limited to, unlike Shinji.
There's also the out-of-nowhere unstoppable hurricane that three of the oldest hollows in existence plus a knight whose entire shtick was wind control not being able to commandeer it or even slow it down because of reasons. You could say Von Geister's plans weren't screwed, but they pretty much were.
I designed Momoka with the same idea in mind. I also made her illusions much more limited in area and scope. There's any number of abilities that people can use in this universe if they're efficient with them to pinpoint Setsurou through his shenanigans. Simple ground movements while he's invisible, pesquisa, the list goes on. In a manner of speaking, while you are obligated to not just have your character's powers ignored, other people's characters are also obligated to not have aspects of their character glossed over as not good enough.
It shouldn't matter if it's his first or his fiftieth. If the character can figure it out, it's a moot point. Besides the fact that Niklaus is not your average quincy, it's another counterargument of 'my character is really good at this, so you shouldn't see through!'. It is just kind of how things work, and everyone has to live with it. It's no more fair to expect Niklaus not to get it.
I didn't want to seem offensive about this, but these points have been nagging at me for a while.