The main advantage of early reading is that it allows the much easier teaching of many other subjects. It is not reading itself which is helped, it is every other subject, since now students can read textbooks, schedules, requirements, and so on without needing the help of others.
And not everyone would go well with that Waldorf idea--take me, for instance. I *like* reading. I learned how to read before I was 6--in fact, before I had any formal introduction. I could read at a college-level in 8th grade, and did (and do), and often. I would have been dissatisfied with that sort of thing, with no books and too much junk that I didn't like as much. So, the key thing to maximize total learning is to figure out what each individual student likes, and use that to appeal to them. For me, for instance, you would want to give me lots of books to read, in all sorts of subject matter, like history, science, mathematics, literature, philosophy (okay, maybe not a first grader :)), and so on. I'll soak it all up and you can leave formal training 'till later. For some other kid who prefers more social play and interaction, the Waldorf thing--deemphasizing traditional methods in favor of, well, play and social interaction, and using that as a basis for learning--would probably work well. Of course, that's really too much effort to be practical, as the people theoretically most in tune with their children (parents) have generally too little time or, especially, too little formal knowledge to be good instructors, while the people who do are professionals, and hence expensive, at least in bulk.
