While I also have no love for Warped, I will say that many DS9 novels suffered from the same problem as the early TNG novels: they were being written while the show was actively being produced, so a lot of their content would contradict the show, and many of the characters were being written differently from how the show would portray them. The ironic thing is that sometimes a novel would have a really great plot and excellent writing despite this, and some novels, well, wouldn’t. Of course, writers can only work with what they are given.
However, on the subject of worst Trek novels, my vote would go to the TOS Errand of Vengeance trilogy by Kevin Ryan. Not because the story was bad, per se, because it wasn’t. Because those three books were apparently not edited at all before they were printed. There were typos and grammatical errors on almost every page, one of the main characters was referred to by the actual actor’s name and not the character she played, many characters were given names of well-known Star Trek production personnel (one or two is fine, but ten or more just takes you right out of the story), and many other problems that even a cursory edit would have made better. Ironically, none of these problems appear in Ryan’s follow-up Errand of Fury trilogy.
However, on the subject of worst Trek novels, my vote would go to the TOS Errand of Vengeance trilogy by Kevin Ryan. Not because the story was bad, per se, because it wasn’t. Because those three books were apparently not edited at all before they were printed. There were typos and grammatical errors on almost every page, one of the main characters was referred to by the actual actor’s name and not the character she played, many characters were given names of well-known Star Trek production personnel (one or two is fine, but ten or more just takes you right out of the story), and many other problems that even a cursory edit would have made better. Ironically, none of these problems appear in Ryan’s follow-up Errand of Fury trilogy.