I find Dukat's "Goodbye, Nerys" in Covenant to be rather poignant because there is a sense that there is so much left to say that will never be said, going all the way back to Necessary Evil, when we see Dukat, Kira and Odo together on Terok Nor for the first time.
Oh, I KNOW! Even with how creepy and psycho Dukat is, that line absolutely killed me when I saw it.
Unlike Kira and Odo, Dukat is never able to transcend his troubled past and make something new of himself. But, as Ron Moore states in that interview you quoted recently, we get the sense that he could have, or might have. And that is sad.
Indeed. He could have been more--but he did himself in with his own choices, and in the end, he paid for them.