CS10 TA here: I have been involved in the development of this course for almost 4 years and in that time I watched it grow from a small 80 student pilot course to a 220 student CS goliath. In my opinion the growth in popularity of this course is representative of an underwhelming high school CS education. For students without some previous experiences, CS61A as an introduction can be brutally discouraging. This fact…
CS61A hasn't been the intro course for inexperienced students for as long as I can remember: What about CS3? I came into CS having never touched or seen a piece of code, and I took CS3 because my understanding was that it was supposed to be the gentle introduction for complete neophytes. I found CS3 to be enormously easy and hand-holdy (it was a little _too_ easy, but that's not necessarily a bad thing for a course meant to be a gentle intro).
What was wrong with CS3 that necessitated the introduction of a new course that (AIUI from the catalog) focuses more on things like the social implications of computing and its relevance to society?