Even at MIT a lot of people struggled with it because they threw so much at you so quickly, and it's since been replaced with a Python-based intro course.
It is definitely challenging and I'm not sure it is appropriate for beginners unless they are geniuses. But the challenging part is not learning Scheme (which is even simpler than Python if not quite as nice to read), the challenge is it works through a lot of computational topics (implementing an interpreter, lazy evaluation, an object system, a logic language, etc.) in a quite compact format.
It's not the right book for 19-year-olds who want to learn programming. It's the book for 19-year-olds who have been programming since primary school. A complete beginner will struggle terribly, and s/he'd still miss most of what the book is really trying to teach.
Lately, MIT has been investing heavily into obtaining a more cosmopolitan image, so ditching a course aims to scratch the itch of hardcore nerds -- while disappointing -- wasn't unexpected, I guess.
