I think the increased influence of parental lobby groups and the like has sanitised cartoons a bit, to the point where a lot of them lack the individuality and unique voice that older cartoons sometimes had just because they were allowed to get away with more. The same goes for a lot of children's programming - even Sesame Street, in some ways the quintessential morning children's programme, has been softened a lot in recent years. I doubt you'd see episodes these days dealing with death and mental illness like some of the older eps did.