It took me a long time to find something better, and I've finally settled on Pico-8. It's the perfect combination of a simplified language that you have to actually type out in a stripped down editor, but with built in sprite and sound-effect tools and game loop methods that you can use to quickly get up and running with an actual 2d game.
It gets right to the heart of the great learning machines from the 80s (Apple ][, C64, TRS-80, Atari 400), but somehow fills in all the bits we've nostalgically romanticized over that would have made those machines a bad choice for kids today. Definitely check it out if you're thinking of getting your kids into programming: