I never really liked THE KILLING JOKE, and consider it the most over-rated of the works Alan Moore produced. And (like WATCHMEN) it had these bland 9-panel pages that you can see were done from a full script, where the artist just followed directions and didn't add anything to the story.
And "the laugh at the end" was just as annoying as "the Comedian is dead" thing in WATCHMEN # 1. I almost only read the first issue of WATCHMEN because I thought it fell so flat, but fortunately I stuck around for the greatness that followed it. WATCHMEN didn't really start to take off until issue 3.
And for me, THE KILLING JOKE never went anywhere. My opinion, it was much ado about nothing.
My favorite Joker story remains BATMAN 251, by Dennis O'Neil and Neal Adams.
And the Englehart/Rogers stories from DETECTIVE 471-476.
