In our introductory CS course at UC Berkeley, CS61A (which is based on SICP but taught mainly in Python), we use http://pythontutor.com to visualize environment diagrams for our programs line-by-line.
If 61A taught me anything, SICP is bad introductory textbook for people who are not directly CS majors: it is not that accessible, and most people just want to learn Python.
I’m not saying SICP overall is a bad textbook; but it is something that can only be appreciated after realizing CS is not only tool for manipulating data.
I want to disagree with you, but you're basically right. The functional way of thinking is different enough it's an unnecessary complication for most non CS majors.
That said, you can teach very solid Computing Science using imperative languages. Algol is still used for research and publishing after all.
Hi Kronopath, the app isn't on the App Store just yet. It was sent for review, meaning it could take another week or so before I actually know whether it will be approved for sale or not.