The problem isn't really that children cartoons have become worse, they havn't really become worse in premise, thou pherhaps in execution (the art styles are detestable, evry show wants their own style, and they dont realize there is a finite amount of styles good for something like a long-running animated series. This might be one of many reasons why anime tends to be better, as in having a single base style they can focus on uality instead of nonconformism at all costs, wich ironicaly makes them often have unique styles that are much MORE artistic, by deferring in much more subtle ways.), the problem is that they exist at all.
"Children entertainment" is an oxymoron concept, an artefact produced by marketing paradigmes and extremly guilable parents. In most cases, something specialized tends to be better as a general rule, hence why parents prefer to show their kinds stuff spesificaly marketed to kids, but what they dont realize is that because kinds have nothing to compare with they will be eualy entranced by just abaut anything, meaning the companies that make them are completly free to cut corners, have no pentalies for executive medeling destroying the story, etc. Childrens cartoons are not made for children, they are made for parent, advertizers, and media wachdogs.
There is no need to give children different entertainment than adults, as long as one avoid a few things, and in fact it is extremly importnant to have parents and children wach the same things and with equal enjoyment, both so that the parent can act as uality controle, and as a valuble bounding moment bothing in sharing the experience togeter, and in having something in comon to talk abaut afterwards.
Besides, there is nothing that indicates that viololence not sexuality have any "coruptive" infuence on children, as long as it isn't in exesive amounts or glorified. Storytelling is one of the most importnant milestones to establish morals, perhaps THE most important second only to parental punishment/reward, while punishment reward by parents establish what IS, stories are needed to establish what SHOULD BE, and having at least one fictional role model is very important in establishing a sound moral phsycology. It is also importnant to be presented by many widely varying ponts of view; show diferent shows from diferent cultures, show both modern ones and clasics, and dont just park in front of the TV, but instead present the chid with theater, cinema, computer games, tabeltop RPGS, books, comics, radio/podcasts, and evry other type of media you can think of, show both uncensured hyperrealism and abstract unrealistic idealism, and evrything in betwen, etc. etc. In short, present evry posible point of view on evrything, and also let judgment come AFTERWARDS, in the discusion and metadata.
Also, the animation age ghetto effect is ruining lots and lots of stuff, the enjoyments adults could have had, the childhoods of those that now get dumbed down junk, and the art that never get produced, all because of this silly prejudice.