Let me know when you do the course on 21st Century replacement for PowerPoint. I have been using Etoys as my Power Point replacement which I believe is one of the uses Alan Kay intended it for. It also has a Scratch like interface (although not as refined and could use a few additions).
Also I just found an interesting on-line Python tutor here which I think addresses some of your goals. It allows learners to step through there code while visualizing what is going on inside the computer. It also has a simple problem specificaion format that anyone could use and allows the specification of multiple tests that your code needs to pass.
I'll avoid quoting Tufte (and sticking a fork in my eye), but will comment that its really the content that matters. Having yet another great technological tool to help facilitate learning and make the production and dissemination of learning artifacts more productive would be a good thing. But IMNSHBOWO, what we really need even more is good content. Ie; good problems and ways to present them. Hopefully folks will be able to point to thier "favorite problems" so we can share and build up a good set of problems (and ways of presenting those problems) for learning.
IMNSHBOWO (In My Not So Humble But Often Wrong Opinion)