I don't really disagree with your rant except that it goes down one very linear line of thinking. There doesn't really need to be an actual village, just a bunch of Orochimaru's secret bases where people can be trained and stuff.
But that doesn't make sense. That would mean nobody did ANY intel on Sound at all prior to the Chunnin Exam.
In the case that there isn't actually a Village of Sound someone would have noticed. And even if they didn't notice that would make Sound a suspicious unknown factor, meaning I really friggin' doubt Leaf would have invited them to participate in the Chunnin Exam.
Chunnin Exam nothing, apparently Sound country bordered the Fire country sooooo…I think intel would have came up big time regardless.
If Sound country is new, where did it come from? A breakway feudal lord from Fire? Then Leaf ninjas would be familiar with the area.
Or is it old, they'd still know the area if it was a ninjaless border country. One does try to know the neighbors of one's patron!
That's why it would have made sense to have a real village (also more interesting).
Also, the comparison is kind of dumb, because Dressrosa is actually the setting for that arc, whereas the Sound in itself was not really relevant, it was just an arm of Orochimaru's power.
If Oda told stories like Kishimoto Dressrosa would not be relevant either, and would be explored roughly as terribly as that samurai place where that one Kage meeting "arc" was set.
Which is ignoring the fact that locations of major villain hideouts SHOULD be relevant if they're painted as being whole communities based in actual countries, rather than some cave somewhere. Kishi's take on this angle would have involved fights with Dolfa members in some generic place, with scant sights of Dressrosa.
If Kishi actually cared about world building, location would always be relevant to show and show breathing and living.
My entire point is that he either doesn't care about it, know about it, or know how to do it. That he sucks at world building. And if he was good at it Sound would never have been irrelevant.
You're thinking entirely in terms of linear plot development, the setting is never irrelevant.