I'll preface this by saying that my wife and I don't have kids. On one side we have a niece and nephew who we probably see half a dozen times every year, one the other side we've got a pair of nephews who we might be lucky to see annually, and we're both approaching the end stages of teaching degrees at university. We have friends with kids, and we've seen the benefits of certain childhood rearing techniques and we've also seen the detrimental side effects that some popular parenting techniques have engendered.
Kids don't need things overly simplified. No more than adults do. In fact, judging by the things that some adults believe on Fox News, it could be argued that many kids have a more sophisticated ability to take in information than some adults. I could also discuss the way I believe that the "satanic panic" against RPGs was actually a conspiracy to suppress open-mindedness and critical thinking in a generation who were starting to transcend the need for organised religion as a crutch for actual honest morality.
I'm more interested in the notion of developmental acceleration in new generations, and the way some media properties have embraced these concepts and others have simply fallen by the wayside.
Look at the old games aimed at kids, like snakes-and-ladders, which really didn't have any thinking in them. They were purely random. Look at more recent games and commercial properties that have captured the imagination of kids, Yu-Gi-Oh, Pokemon, various form of anime... don't look at things that adults are trying to aim at kids, like the pink dolls in the girls section of toy stores, the guns, tractors and trucks aimed at boys. We're getting more and more anecdotal stories where kids are asking why there aren't "Black Widow figures among the Avengers", stories where girls just want to get one of the "fun" toys from the boy's aisle, stories where boys want something from the girl's aisle. Kids know what they want, they want to make choices for themselves.
A game aimed at them needs to offer choices, and if it has lessons to teach, it needs to do it under a layer of fun. It needs to draw kids in first, and teach something second.
We can have development in the game, Pokemon shows us that this is fine, and is actually something that kids might look for in a game. It changes things up and keeps things interesting. We can have symbolic concepts, and certain educational theories state that these probably work better than numbers and complicated words. Archetypes bring shorthand techniques for getting kids to understand the game and the setting, in much the same way that stereotypes and genre shorthand sets the genre grammar for an adult when they go to the cinema to see a movie (or read a book). I was heading in this general direction in my third submission to the 200 word RPG contest. My aim there was to produce 200 words that would give hints to the way symbols would work, then circumvent the rules by explaining the rest of the game through interactions between those symbols.
It was vaguely working, but taking too long to get right. I might revisit the concepts from that final game here.