Supposedly John K., to make sure Nick would approve the story, changed Ren from an executive to a producer and said he was just poking fun at himself. Which he wouldn't have done, but the Games crew did.
But the Games crew not only did that but improved the story. Raymond Spum, John K.'s fictional Uncle Walt-esque founder of Spumco, was substituted with Wilbur Cobb, perhaps one of the show's greatest characters.
Stimpy's cartoon was also going to turn out to be good in the end, but Games instead decided to make it incredibly bad and therefore much funnier.