"As I said before, no one is 100% evil in every way. Any villain that is written that way is a cardboard character and a cartoon. We look at Dukat as a fully fleshed out character with sometimes conflicting motives and emotions. But – and it’s a big BUT – there is something dark and ugly in this guy’s soul. Explain that away with his poor childhood or his life experiences all you want, it’s still there and the result of it has been pain and suffering for literally millions of people. And I don’t buy the argument that just because Dukat’s grip on reality was a bit shaky in “Waltz” that we can’t hold him responsible for his actions in the past. The hell we can’t. He wasn’t crazy when he ordered those reprisals against the Bajorans or ordered them into labor camps or burned their villages or commanded an army of occupation that terrorized an entire planet. Yes, he’s interesting. Yes, he’s charming. Yes, he can even be funny and likeable on occasion. But those are the reasons he’s been such an interesting villain, they are not reasons to excuse his behavior or try to wash away the blood on his hands."

—Ronald D. Moore (http://en.memory-alpha.wikia.com/wiki/Memory_Alpha:AOL_chats/Ronald_D._Moore/ron081.txt)