Basically, The Laertian Gamble happened because John Ordover, who was editing the Trek books at the time, is the world's biggest Sheckley fan and couldn't resist giving one of his all-time favorite writers a shot at writing a Star Trek novel. It was an experiment that perhaps didn't pan out as well as everyone hoped.
I think the problem was that readers would've been expecting a tale in the style of DS9 and they instead got a tale in the style of Robert Sheckley. Naturally if you bring in one of the legends of the industry to write a book for you, you let him do whatever the hell he wants, but that doesn't necessarily produce something that feels like the show. So it's that cognitive dissonance, I think, that threw so many readers.