Perhaps connected to the related searches...
I've recently been seeing, beginning roughly Thursday (April 14), that, for a given query, Google appears to be shifting the entry page it returns for a site to pages that it's deciding are more useful. It could have been happening sooner.
In one case, Google dropped an inner page that was optimized for the query and returns instead the home page, much less traditionally optimized for the query, but which is a better entry page to find the related pages.
On another site, which ranks number one for the single word "widgets" (competitive, with 26-million pages returned for the word), I'm observing a shift in the other direction... ie, from the homepage to an inner page for this term. The home page is loosely Brandname Widgets, and Google continues to return the homepage for [brandname] searches, but for the single word [widgets], it's now returning the main catalog page, which links to the main widget subcategories.
These pages may have been returned as clustered or "more results" pages from time to time, but this is the first time I've seen them ranking alone, replacing the expected page.