There's certainly room within Trek Lit for authors to express their own distinctive voices and worldviews. My Trek novels are profoundly different in style and tone from, say, Peter David's or Margaret Wander Bonanno's or Diane Duane's. You read a Trek novel by Duane and you're reading a Diane Duane novel, a book that's in much the same voice and conveys much the same ideas and sensibilities as her original works like the Young Wizards series. You read a Trek novel by David and it feels a lot like his comic-book writing or his original novels, with the same edge, absurdism, and snarky wit (and having conversed with him at Shore Leave just weeks ago, I can safely say that the way he writes is the same as the way he talks). You read a Trek novel by me and you get the same hard-SF sensibilities and the same overall voice and attitude that you'd get in my original work, allowing for the need to adapt to the ground rules and tone of Trek.
But as I said, the key is balance. If a book doesn't feel enough like Star Trek
, or if it gets certain things about it wrong, then that can alienate readers. Not to mention that a number of original-SF writers, let alone "literary" ones, tend to see tie-in writing as slumming, so they might look on a Trek novel just as a quick-and-dirty way to make a buck and not put a lot of care into it, if they bothered to do it at all. The best tie-in writers for a given franchise are generally fans of it, people who really know it well and care about it and are willing to put their best work into a tie-in novel about it. You can be an accomplished original/literary writer and
love Trek and thus produce really top-notch Trek novels -- but if you're a hugely acclaimed, accomplished author who's never been much of a Trek fan and doesn't have strong feelings about it, then your attempt to produce a Trek novel might not work very well as either a Trek novel or a self-contained literary work. After all, good writing entails passion toward your subject.
I'm reminded of what happens when respected "mainstream" authors decide to dabble in science-fiction themes for the first time. All too often, the ideas that they think are so fresh and innovative and daring are things that more "lowbrow" SF writers had already mined quite thoroughly decades before, and are just warmed-over cliches that aren't even handled as deftly as the SF writers did. I was once at a book fair event seated next to an author who was so proud of this book he'd written as an attempt to plausibly extrapolate where our society was going and where it would be in 30 or 40 years, so convinced that it was this revelatory, cutting-edge piece of work -- and I didn't have the heart to tell him that he was just rehashing a bunch of hackneyed, obvious dystopian-future tropes that science fiction had beaten him to by decades and already thoroughly played out in countless books and movies. It doesn't matter how accomplished you are in your own field -- if you switch to a new field, you're still gonna be a beginner there.