And, strangely enough, he wasn't the most evil villain in Karen Berger's line of books. That "honor" went to Anton Arcane from Swamp Thing. Arcane was such a sicko that Dr. Psycho would probably say, "That guy's a sicko." :)
That's why, as big a Joker fan as I am, I've never bought how he's played up as the scariest, sickest, monster out there, the whole bit about how when villains want to scare each other, they tell Joker stories, etc. There are a lot worse than him. At least you know the Joker isn't planning to eat you, unlike Dr. Barbara Minerva. :)