@RedSquiggle made the comment, but yeah. 3 Act or 5 Act structure. Unless you're writing experimental fiction, that's what's expected.
I'd go so far as to say the 3 Act structure is not just what's expected, it IS the structure of a true story--something that looks, smells, feels like a
story. What the CriticalHit is effectively saying in that video is that all stories are good stories (in the sense they follow a 3 act structure) or they aren't stories at all. "Poorly structured" attempts at story are not really stories (even if the author wants to see it as such), but merely rambles.
The final part of that video is CriticalHit going through the process of refining a story until it said what it was he wanted to say. And lo and behold, it had a 3 act structure by the time he was done. Thesis. Argument. Glorious conclusion. Is it an award-winning creative effort? Certainly not. But it is satisfying in its fullness and therefore demonstrates the point.
At first, I found this Youtuber's opinion to be at odds with Stephen King's opinion in
On Writing. King argues for putting the "story first," then refining and highlighting any inadvertent symbolism or message in later stages, whereas CriticalHit argues for putting the message first, and refining the story until the message rings out (he says that all stories are attempts to tell us how we should live). However, these approaches are only at odds if you think a writer can write without expressing their views about the world. That is, of course, ridiculous. The only difference here is that one is a conscious attempt at message, and the other isn't.
You can argue for which approach feels more enjoyable to you as a reader until the cows come home, but the creative process offers so much play and flexibility between imagination and worldview that only a real Edward Bernays kind of author would let their craft suffer under the thumbscrews of overt moralism
. If there's no
play, then it's not the art of story-telling--it's just propaganda.
All of this to say, my humble opinion is that writers suffer unnecessarily under the so-called rules of structure. Your very thought processes have structure, so structure will be intrinsic to your finished product. If the structure isn't there, if it doesn't "ring" like a true story, it only means you're not finished.