I think there is a world of difference in the "average total beginner" high school students taking a class to meet a district mandate, and the "average total beginner" self-motivated learners actually interested in computer science.
You really, really have no idea how difficult precise logical thinking is for an average person.
have you looked at: etoys scratch starlogo alice or scheme ?
At some point soon, I'm planning on moving to something where they can distribute what they're doing, either as JavaScript, or pygame, or something. I'm hoping to be able to literally translate a scratch program to the n+1 environment so that they can see the equivalence of the looping constructs and the event handlers and everything else.
I can't imagine anything that would have pleased me more than being able to show off my own web site when I was that age. Of course, making silly web sites for myself is how I got into programming in the first place, so I'm probably biased ;)
* Runs everywhere. It's the BASIC of this age * It's not that bad. * They can do stuff their friends can see
I'd rather do python, since it's that much cleaner, less curly braces and semicolons and better loops. But, the results aren't as public, and it's a harder environment to set up. And given that I have to work with the school's IT, I think I'm going to be lucky that we can load chrome on the system.
So, clarity for teaching, or ubiquity. Still deciding.
I will say that Stacy Armstrong's "A+ Computer Science" curriculum is quite good and well worth the money.
I've taught Pascal and C++ before, and dabbled in Scheme, too. In my opinion, Scheme is lower-friction than Java, but precise logical thinking is hard in any language, and precise logical recursive thinking is even harder for the average student, which negates any syntax-related benefits.
My kids are very successful in Java, and so I'll stick with what's working until the College Board changes the language of the AP exam on me.