Whereas I like your effort on explaining why you think Yata is not what the hype is saying, you really haven't proven your point (with facts anyways). I find it very difficult to believe that something that can change its physical properties to match an attack will have problems adapting to light and sound. I can use any opaque object to block light, you think a spiritual shield will have a problem turning itself opaque? I don't think so. Also sound-proofing is not that hard either, just absorb the vibrations or dispel it and you are good to go...sand comes to mind as I say this.
As other people have said though, the burden of proof is on your side and you haven't done so yet. When something...anything gets through the Yata shield, and causes some type of harm to its owner (Itachi), then we can say that the databook (which incidentally has more facts than things proven wrong) was exaggerating about its ability.
Yet, I didn't see this properties changing in the manga. If you're willing to mention the databook, you might as well consider that every susanoo has yata and totsuka.
Once some source of information starts to presnt multiple flaws, it can no longer be taken as "law until proven otherwise". Why? Because it's the same source of information. It no longer has a 100% of veracity, but a smaller %. So, there is a chance, and a considerable chance, that the information of that source is incorrect. We can't take that risk.
So, no. Databook is no law. It is an information that might be correct and complements the manga, but first, it must be analysed to see if it fits manga logic. Believing blindly in something already mistaken in the past is stupid.
we discuss about the manga, as the stories, the plot, the chars, everything is first and mainly presented in the manga itself, not in the databook.
The databook was supposed to be an adcional information, a book that would explain and list somethings better. But it failed. Once, twice, many times. That's because either kishi doesn't want to spoil or that he changes his mind. However, when he changes his mind, he adds the new logic/rule to the manga first, and sometimes, he doesn't even bother to correct the databook.
The manga is where the events happens, is where the logic of that universe is created. The manga is the narutoverse, not the databook. That's why it has more credibility, and it will always have. It will present mistakes and incosistences, of course. But due to the above, it holds more importance than the databook.
Considering how the shiled was presented in the manga, my explanation stands, since I used drawings in the manga and logic to prove my point.
