TL;DR For a layperson, the association between dataflow and 'real coding' is very weak. For a programmer on the other hand, the association may be less weak, but the skill may nonetheless not be applicable to most real world applications.
Excel is basically a dataflow. You can avoid talking about loops with maps, that can be understood immediately with excel tables.
Something like Excel that does not divide so strongly between cells and VBA should be ideal. Resolver One was very interesting.
That's the approach that I think it's the best: Excel is right now how people that need sort-of programming but don't program bridge the gap. It's huge. It's everywhere. And it's _VISUAL_.
Perhaps a simplified Excel for educational purposes is the ideal way to expose people to programming, formal thinking, systems thinking, functional definitions, etc. And, when they jump to real-life Excel, and get culture shock, perhaps they keep using that original program that they were taught.
Perhaps there is a viable startup here....