What good is Feedback when Google is determined to take away features from something like Google Books? You can complain all you want but they won't revert. Just making it easier to complain does nothing to fix anything.
The difference is subtle, but important.
Feedback: "I would use your product more if it did x."
Complaining: "Your product sucks because it doesn't do x."
In short: you're absolutely correct. Making it easier to complain doesn't help. Making it easier to give feedback does help.
The specific functionality they took away is devastating to regular users like me. When searching, results would show if a book was already in your library. You could also add it to a shelf from the search result itself. Now the search results lack that info and you must click on each result to see if it's one you already saw. This is sheer hell for discovering books that weren't there between searches.
[edit for URL fix]