This Scratch thing reminds me of Authorware. Fun and powerful if you are still at a point in life where you are terrified of coding with text. But after you outgrow it you regret not using those brain cells to learn conventional programming. (At least, I did.) I'm not saying it's without value, but I am saying it can lead to disappointment.
One thing to remember is that Scratch can 'kickstart' the learning process.
For kids being able to quickly display graphics and move them around offers a big buzz and gratification very quickly. With a lot of other programming languages the gratification is greatly delayed which can make people quickly abandon them unless they already have some experience in programming.
Not sure I can name another programming language that you could give a 12 year old and they would be able to self-start and would not be likely to abandon learning it if they follow the standard 'get started' guide for the language. Unity is possibly the next closest, although it is much more complex to learn.
