One of the issues, too, is how both treat their narrative. Trek's universe is just as horrifying and full of monsters but the Federation actually punches the horrors back while (mostly) maintaining their morals, but the Imperium can only grimly hold on and has to meet atrocity with atrocity. Optimistic vs. Pessimistic.
If somebody wrote a story where some rando Imperium researcher came up with a "cure" that turned Orks into peace-loving allies of the Imperium it would be a ridiculous violation of all the themes in the game. If there was a DS9 episode where O'Brien and Dr. Bashir travel through the wormhole, encounter a functionally identical race to the Orks, and Bashir was able to cure the genetic tampering that made them violent in the space of one episode, it would just be a fairly typical episode of Trek.