>>>Thin pages cause substantial bigger problems for a domain
Also the definition of "thin pages" has changed. Thin pages used to mean content pages with very little content.
Apparently this has now also been applied to directory pages, index pages, and user generated content. Google has no ability to differentiate between crappy, thin content and legitimate pages design for organization or for user profiles, etc.
It just counts them all as the same thing and applies a big penalty.