We're in the amidst of creating something complimentary (different too) to Codecademy called http://CodePupil.com. We're eager to see different styles of teaching; especially examples where gaming is used!
As noted in the OP's article creating a new experience and especially one that teaches all the Elizabeth's how to code is a big challenge. We've been asking our friends like Elizabeths to test and then we reiterate. Also we've found Mechanical Turk to be helpful in re: to user testing feedback. There seems to be a lot of Liz's there.