Pages were re-written wholesale, and new pages added to make the whole site more relevant to the targeted search terms
Many folks are also saying re written content is not helping them to bounce back.
@superclown2 - How big is your site and what is your TBPR of home and deep pages. Do you have any authority links into your site.
Although I wouldn't expect your site to bounce back, due to the manual process Google is declaring, I think it would be interesting to see if your site's size and authority came into into at all. Folks have long discounted the notion that this update was link related, but if the content had little authority and link juice it may have been more vulnerable. Just a hunch.