Usually, Doctor Who episodes get better the second time I watch them, as I pick up more of the story and see the nuances and hidden meaning. Even episodes I don't like get a little better (though there are many I don't care to see a second time, like "Love and Monsters" and most of series 8 and 9); one that didn't was "Journey to the Centre of the TARDIS". Unfortunately, "Time Reaver" joins that list.
The base story was good enough, though uninspired: a naive girl assumes that the people will use dangerous technology only for good and tries to bring it to the universe, and an evil smuggler tries to make a profit off of it and uses it to torture his enemies, and the Doctor has to stop the spread of the weapons. However, the whole premise doesn't really hold together. The Vicentians are described as being highly advanced and completely agricultural at the same time. They're a "collective" race, yet Cora has no collective tendencies. The time reavers themselves seem to have different effects depending on the plot: Cora gets shot with a tiny dose and it lasts for a few seconds real time; other people get shot with a regular dose and it lasts for at least many minutes (enough for them to be found lying in the streets and get carted away by the militia); the Doctor gets shot with more than twenty doses and it lasts only ten minutes.
I think, though, that what brought this story down was the execution - it's almost like it was shot by a time reaver itself. It's paced very slowly and takes a long time to get going. (Perhaps that's its theme.) When it finally does get going, it is interrupted periodically by slow, drawn-out scenes of people being affected by a time reaver. It was interesting the first time, but not the third; I was rolling my eyes during Gully's. And in contrast, when there's a person whose reaver experience you do want to see - the Doctor, of course - that isn't shown. I was also disappointed that the Doctor was seemingly unaffected by spending seven centuries in his own head, and that Donna displayed only curiosity about it, and not concern and compassion.
The audio also suffered from the background noise being too loud in some places; this is something that happens more often than I'd like in Big Finish audios.. Even on the second hearing, I have no idea what was said during the Vagabond's Reach scene. I understand what happened, but the dialogue was completely obscured. What are "blues", by the way? Is that a British slang term? Also, sometimes, the sound effects on the voices made them difficult to understand, especially on Gully.
The episode could have been carried on the Doctor and Donna's shoulders, but even in that respect, it was lacking. With the emphasis on the time reavers themselves, there wasn't much time left, or opportunities left, for the two interact much outside of the opening scenes, and what they did have didn't sparkle like it should have.
The story did have two things that I want to point out: the planet itself and Soren. Calibris, the artificial, metal planet that serves as an intergalactic transportation hub, is fascinating. It has no law, no police, except for the Vicentian militia who was brought in to solve one problem, which should make it a maze of petty politics. The psychic earplugs removed a lot of the uniqueness from the setting, but they were necessary for the story, so we can excuse that. I'd like to see the place explored a lot more (and I'm very tempted to send David and Will there someday). Soren was the mechanic that the Doctor came to Calibris to visit, to get replacements for his blown fluid links. There's a lot of mystery about him - how does he know about the Doctor and about maintaining a TARDIS? - which is not explored. There was a missed opportunity here, to create a character as vibrant as Drax ("The Armageddon Factor"), a similar character that caught the imagination of the audience but was never explored further except in a novel. Soren's another thing from this audio that I hope to have the opportunity to use in my own fanfic.
Last kibbitz: The reference to the Library at the end bothered me. When the two went to the Library, Donna specifically complained that they had been headed for a beach and instead, the Doctor brought her to a library. The Library wasn't their intended destination at first. I love it when new stories reference established canon, but not when they get it wrong. It's possible that "Time Reaver"'s mention of a library was not meant to imply that they were about to head for the Library, but if so, why include it at all?
So, at the end of all this, it wasn't bad, but it wasn't good. My rating: 6/10