I've said it before and I'll say it again: Dukat losing his mind after Ziyal's death and going into Federation custody was the best way to end his story. It wasn't like the episode redeemed him in any way. I would have accepted Dukat and the Birth of the Super Cult if it culminated in Kai Winn fully betraying him and turning into the main antagonist in the last season. Winn's character represented moral cowardice leading someone to commit ultimate evil, which is very compelling, while Dukat was always a rotten bastard. There wasn't anywhere else for Dukat to go, thematically speaking. However, Ira Steven Behr had a weird hateboner for Dukat and the viewers who saw Dukat as anything but comically evil. It's really unfortunate.