New Yasou players wouldn't understand why these things aren't being blocked despite it being what the ability said it would do, especially when other abilities still behave normally with wind wall.
New Yasuo players are confused that Wind Wall doesn't block Xerath Q's, Xerath Ults, Tower shots, and melee auto attacks. Seriously, count the number of times new Yasuo's will cast Wind Wall while 1v1ing a melee only champion, it's very amusing.
Again, I'd argue there'd be less confusion for new Yasuo's because it matches the lay man's definition of a Projectile. Rocks breaking under your feet are not what the average person would call a projectile.
PS: remember that Yasuo ults Airborne targets, yet isn't able to ult Anivia, Kayle, nor Aurelian Sol on demand. "Clarity" was not a word in Riot's vocabulary as far as Yasuo is concerned.
Remember, there is no actual way to distinguish abilities that "Travel across the ground" because the projectile itself isn't on the ground, only the animation.
There's currently no way to distinguish, but a boolean (true/false) attribute could be added to identify if the traveling spell is considered a projectile. Default attribute to true, set it to false for ~5 current abilities, and have the functionality available in the future to use that for new interactions.