Isn't Red a great language to teach children? I just tried Red and it's amazingly simple to get started.
Although Logo is said to be an ancestor to Rebol (which in turn is an ancestor to Red), there's more it than an apparent "childish" simplicity on the surface. http://www.rebol.com/article/0103.html Language that hits the sweet spot between Forth and Lisp might be a good fit for some kids, but its scope is way outside of mere scripting and toying, and demands a respective approach - something that only grown-up engine…
Maybe I misunderstand where you are coming from, but to me this appears similar to saying that using acrylic paint demands a respective approach because the great paintings of the last century were made with it.
To which I would say: no, not really. Acrylic paint only demands a respective approach in the sense that it may be toxic and you don't want kids to finger paint or risk swallowing it. But people can paint whatever they want with it.
Similarly, Red demands a respective approach because it's powerful enough to shoot yourself in the foot (oops, some kid deleted half of the files on the SSD by accident). Maybe that is what you meant with "scope", but it's not what I made out of it upon first reading.
Besides, the solution for that is simple enough: make a child-safe dialect.