About the way cartoons are changing since the 80s, let's consider something a little different, but not much: The Dark Crystal. It's a Jim Henson muppet movie, but not at all like "The Muppet Show" muppets. In Holland rated as appropriate for children 6 years and older.
There's a death scene in it, quite soon in the movie. You see a very "old" muppet literally gasping his last breath, upon which he fall back on bed and begins to crumble. Well, I hear you think, how scary is that; they're muppets after all.
Have a look-see:
I truly doubt the MPAA's politbureau would rate it lower than 10 or so. And then I'm not even talking about the death scene, just the look of the muppets. Could be wrong though as I don't live in the USA.
Btw it's a great movie. It has its share of problems, like being a little slow some gaping plot holes, but the rest really makes up for it. We might see what the MPAA makes of it when Power of the Dark Crystal comes out, if ever.
Cartoons seemed to start consolidating in the 90s, plot wise. It all seems so standardized. The jokes that'd go over the kid's heads disappeared, only to come back in the new millennium, and only in movies, and probably only because there was a new animation studio in town.
And the crummy advise sections at the end.. I suppose someone got it through that it was a joke. Everybody thought so. We made fun of it, parents made fun of it, everyone..
Hacking and slashing in a loincloth and then, with the mandatory pointed finger, telling the children to remember to floss is ridiculous.
Same goes for hacking and slashing, killing who knows how many and then, again mandatorily at the end of the show telling a crummy joke, the show ending with a "whoh hoh hoh hoh hoh" of the whole gang is equally ridiculous. Glad they cut those too.
EDIT: the Nostalgia Critic did an interview with the creators of Animaniacs in which the topic is also discussed, and how the creators tried to fool the rating office:
http://thatguywiththeglasses.com/videolinks/thatguywiththeglasses/nostalgia-critic/27685-nccommentary-animaniacstribute. However, this is starting to get off topic.