I mean, I doubt you are in any position to judge the writing of PS:T just based on descriptions of it.

The writing of PS:T is vastly better than an “Adventures of Drizzt Do’urden, part 153” YA fantasy novel or what have you. Perhaps it wouldn’t win a Pulitzer if it were a book, but for a computer game the writing is incredibly good.

But what’s really shocking about the writing is

1. How much of it there is

2. How well it showcases the utter weirdness of Planescape compared to your standard D&D settings like Forgotten Realms

3. How it subverts, inverts, lampshades or in any other way plays with every major high fantasy and D&D trope that you can think of. Whatever you have heard of the writing, there’s nothing generically “D&D” about it.