Really thought-provoking article! I've been teaching students to code for seventeen years, and your experience dovetails with mine. (Disclosure: I'm also the author of 'Learn Java the Hard Way'.)
I must admit that I'm skeptical that any "regular" student could learn Java well enough to pass the APCS exam in only twenty hours.
Can you explain a little better about the population you're working with? These are high-aptitude students with prior programming experience, no?
their prior programming experience varied, though there's certainly bias in who would sign up for coding tutoring (free or paid.)
all were comfortable using computers, and they'd seen code before. about half had gone through a Girls Who Code summer program (http://girlswhocode.com/programs/), which is designed, i think, to overview technologies more than drill concepts. they all had computers had home (about 50-50 windows/mac) with new-ish chrome or safari.
i only had one student take the multiple choice questions; he would have gotten a 3 or 4 on that part. he's coming off SAT prep and is good at taking standardized tests; he was weakest on the test's particulars ("how many bytes in an int?") i spent very little time on those sorts of questions; my view is that a motivated student who can understands how computers think will learn those particulars if s/he wants a 5. and for those who don't, there's google and stackoverflow.
i asked students to answer old free-response questions in the editor that's shown in the fizzbuzz video. that worked really well; with the help of the compiler, they were able to ace those questions. (i know you don't get a compiler on test day, but it seems silly to cripple them when learning.)
sometimes i tutored in person; other times, i did so over google hangout. either way, i was working one-on-one with a student, and it was painfully clear when s/he was confused, whether it was over a CS concept or a tool i'd introduced. tutoring also meant it was my responsibility to "fix it", and i think that explains a lot of why i cut 160 classroom hours to 20 tutoring hours.
And I now see that you're saying that teacher "touch" time was 20 hours. Which seems doable if they're able to teach themselves with proper tools.
> "with the help of the compiler, they were able to ace those questions. (i know you don't get a compiler on test day, but it seems silly to cripple them when learning.)"
Oh. This is where we're going to have to agree to disagree. For the AP exam students must write code on paper with a pencil, with no computer in sight. It's been my experience that students that don't have quite a bit of practice doing that without any training wheels crash and burn on the exam.
i suspect you're right about needing to hand-write code -- especially if you're used to things like code snippets and autocomplete. i suppose i feel about hand-writing code the way i feel about understanding compilerish: you'll probably have to do it at some point, and it's a skill worth practicing, but i don't think it should come first.
And I think we agree more than we disagree; teaching kids that they can code and how to think algorithmicly are far more important than getting them ready to pass a single exam.