The best thing about this is that Anderson and Duchovny are talented actors, because any other players (like some of the supporting cast) would have rendered this whole thing regurgitated dog food, rather than just dog food. They manage to pull primarily very weak and hammy scripts into the just acceptable.
The TV reboot recently got pretty crappy reviews from many unhappy fans - I actually got a bit of a kick out of it, especially with the more quirky storylines in the vein of Jose Chung's From Outer Space, where the classic Mulder humour comes out. It was far and away superior to Cold Cases.
I think I read that this Audible series was adapted from the graphic novels of and by Joe Harris, and perhaps this is why it went so wrong. Comics have pictures. Comics don't have to infodump what you can see, and so the awkward way the stories were translated into what were basically radio scripts was bad. It's interesting because David Duchovny actually highlighted this point - that there are no visuals and so the scripts must be top notch - at a convention. Unfortunately, his very show fell prey to the opposite.
I'm also not sure why they bothered writing in characters where the original and long-running actors were not going to return, as I found it distracting and forced. The actor for Krycek tried with the material he had, but he was so obviously not Krycek it really got on my nerves. As did the Doggett actor. If you take the strains to keep the world of the X-Files intact with Mulder and Scully, Skinner, and TLG, then don't ruin it by imposing on our expectations with faux portrayals of very well-known characters, unless you're recasting the WHOLE thing.
Overall, this added nothing for me in the X-Files lore, and I'm not sure it was even necessary in 'closing' old cases, because, well, they kind of opened new ones at the same time. I will, however, be listening to the next effort, because they can only learn from experience, and it's The X-Files.