Firstly, I'm not trying to pick a fight.
Think of it like this: I'm willing to believe that Ren is honestly exploring the world as he goes (as opposed to having picked something "because it will make a good series" as at lest one YT commenter has claimed), and if he lets out the world seed, eventually his comments will end up flooded with "you should go here to get such and such resource" or "go to coords x/y to find a village with awesome trades/rare biome resource" and so on.
Besides, there's a lot to be said for not knowing, as a viewer. Another layer of "magic" as it were. And before anyone goes thinking Ren got super lucky or "super lucky" with his seed, I've random spawned virtually on top of abandoned mineshafts entirely too often on standard world gen. But I play with subtitles on, and *rolling minecarts* appears sometimes before even *running water* when I'm near a river/ocean delta.
Again, not trying to pick any fights. Ren is a great entertainer. So I just settle back with my crunchy snack and tasty beverage and let him entertain me as he sees fit. I've yet to be disappointed. Except one time with his audio (tinny sound), but he's long since gotten superior recording equipment. I mean, I've even watched him play a few minutes of PUBG, and that game has zero appeal for me. (He's lost me at Rust, though; nothing on this green earth is likely to make me care about that game.)