>> Good English used to be one.

There still is a cottage industry of people saying one should write this way and that, and by large they have converged to a common consensus of what's Good English. It has been a successful enterprise, and now LLMs excel at generating text inside those parameters :-) .

Now, whenever I review a book, and if it applies, I make a point of saying "the grammar and sentence structure are squeaky clean". Often, that's about the only good thing I can say of the book.

I wonder if Good English is correlated with follow-the-norms attitude in an author+editors team. Because, once you make follow-the-norms your god, it is guaranteed that the writing will be formulaic and uninteresting. And then the only thing that can save your writing (financially) is good marketing.