I really do think the target audience does matter in how the show is written. Like take for example Spongebob which everyone of all audiences enjoy. I mean you cant be a 17 year old and watch Spongebob and expect to see Emmy - award winning, smart, intriguing, mature dialogue. You'd be insane if you thought you would.
And I wouldn't really call Kanto mature. They probably got rid of the slapstick comedy because 4kids might've complained about the violence.