Star Trek: 10 Things You Didn't Know About The Cardassians
2. They Were Humanised So Much That They Stopped Being Villains
Ira Steven Behr believed that, by the time Deep Space Nine's fourth season debuted, the Cardassians had become so muti-faceted that they were no longer purely antagonists. This, combined with the rise of the Dominion, and the outbreak of the Klingon war, pushed the Cardassians out of the villainous limelight.
Behr believed that they had become so complicated that it was difficult to hate them, whereas Robert Hewitt Wolfe countered this. He explained that, despite understanding the Cardassians, this added to their complexity when these people committed truly heinous acts.
Introducing the Civilian Government was meant to soften the Cardassians, but only temporarily. Having Dukat switch sides in The Way Of The Warrior was well within character for him - as Sisko said, he saw which way the wind was blowing, and switched sides. Yet this is the same man who then negotiates with the Dominion in the fifth season.
In Dukat, the Cardassians are exemplified as more than any one thing - no matter how unpleasant some of those things may be.