So I finished Mario Wonder so I can watch the playthrough of one of the YTers I currently follow without ruining any of the surprises, and if I was a pro game dev I'd pay next to anything to get a running feed of their thought processes to try and understand how they're exploring the game and learning to play it.
I'm now all but convinced there's genuinely no accounting for game literacy in game design. Certain conveyances in the game that I thought were so obvious as to be literally elementary soared so far over their head they went into fucking orbit. They don't tend to act out to the camera, very scarcely interact with chat, and seemed to be very focused on enjoying the game; so I genuinely don't think it was the "streamer effect" at play.
And I don't mean to make myself sound like I'm saying I'm better than a speedrunner (they used to do that back in the day); there's likely going to be a lot of stuff they'll figure out automatically that I struggled with myself.
While looking up information about Yoshis' and Nabbit's mechanics, I found two articles that concerned me: one that explained the mechanics but failed to do so in any sort of detail I was hoping for, and another that complained about Yoshi not being allowed to pick up powerups and how this "denied them an integral part of the experience" because they weren't made aware of it until several levels in - when the character selection screen has a warning plastered across it that explicitly says as much. The YTer I watch made the exact same mistake, multiple times.
It's just so fascinating and a little frustrating how, at least in practice, nothing can be assumed to be "obvious" in games - even if and when it's written in plain language front and center.