If you're unfamiliar with Dev Commentaries in Amnesia: The Dark Descent, they're the yellow microphone icons in the game providing meta information from the developers themselves about the development of an area you're currently in.
Of course, there is one slight catch. They need to be enabled in an options menu.
Furthermore, development commentaries due to their "meta" nature, throw the player out of the experience and the immersion. That, of course, is unwanted for most of the narrative custom stories made for Amnesia. In the original game, it was most likely meant for a second playthrough, however, in the custom story community, it is rare to find a custom story worth a second playthrough.
And so I would argue that there is perhaps a third option. Instead of not communicating this feature to the player and hoping he or she would turn on Commentary AND give your story another go, how about we implement the commentary into the space between the end of our story and the credits.
A great way of doing this would perhaps be an option to either go through development commentaries or to quit out of the custom story.
In When I am no more, there is a set of established features, like achievements that already provide a place that acts as a blend of in-game environment and a menu. Allowing for the developers to put extra content without concern about the story and immersion. After all, the story is over at that point.
This idea is very common for Garry's Mod horror maps, where it most likely happened due to a lack of custom credit sequences. And I would argue that more custom stories should have similar "end rooms" as I'm going to call them from now on.
Providing space for custom content and of course, Development Commentaries.