All in all, I like where this is going.
I feel like somebody like my parents wouldn't know where to click (or even start to look) if they were looking to buy a book.
I hardly ever browse by category, they're too generic. Whenever I'm looking for something on Amazon, I go right for the search bar.
This new design makes an emphasis on search so I'm guessing Amazon noticed that other people use the same the same way I do.
Edward Tufte seems like an influence on the redesign. https://secure.wikimedia.org/wikipedia/en/wiki/Edward_Tufte
All in all, I like where this is going.