This is dependent entirely upon what cartoon shows you're referring to. There's been an entire culture of adult-centered cartoons (all of adult swim, for example), that I think are equally worthless for adults and children alike.
When I look back at the cartoons I watched growing up, nostalgia is the governing emotion, rather than reason or criticality. Most of the things I watched, if I really sit back and think about it, were absolute garbage. Some of the daytime cartoons I watched had good messages, but the majority of things were just as vile as what's available now.
The question I ask myself about children watching TV is if it's something that's entertaining without providing too negative of an influence. When you're a child, you're interested in shiny things and fun characters, not the subtexts of a program. For many young people, watching "bad" shows is more about being able to say they're allowed to watch them than it is any real interest in the content.