I want to see something that grows with you, and you can use it from childhood right up to the enterprise.
It was bout 20 hours of programming concepts in Scratch, and then 10 hours of transferring their learning of Scratch semantics into Python syntax.
Most of the younger students in the class wanted to keep playing with Scratch, but the older ones intuitively understood they could go far with Python -- and that Scratch was a nice place to test/debug algorithms before implementing the "final" version in Python.
John Maloney, who was not mentioned in the article but was the key person to making Scratch happen is working on:
https://wiki.scratch.mit.edu/wiki/GP_(programming_language)
One of the links on that page is to Snap! which was used to introduce programming at Berkeley. You can use it as a Scratch written in Javascript and so able to run in any web browser. The extensions are a bit clunky, but pretty interesting.
In my view a benefit of Scratch is that teachers can learn it.