The lack of a Google Search box doesn't affect much as users can now search by typing within the address box, much like in Google Chrome. The lack of an RSS button is a bit trickier, however.
Safari no longer includes RSS detection and one-click subscriptions to RSS feeds. For users looking to get that button back, Daniel Jalkut of Red Sweater Software -- makers of software products like MarsEdit and Black Ink -- has created a "beta-quality, more-or-less unsupported" Safari Extension called Subscribe to Feed.
[The] extension adds a handy button to the toolbar that, when a page offers RSS or Atom feeds, can be clicked to easily open the feed:// link, which should automatically open your favorite news reader.The extension works as advertised, however it falls flat when used on a website with multiple RSS feeds. MacRumors, for example, has four RSS feeds listed -- one for the Front Page, two more for the Mac and iOS Blogs, and one feed that lists every post to the site.
We've reached out to Jalkut to ask if this limitation is something that could be easily remedied.
Update: Daniel Jalkut, the designer of the extension, says he'll "be looking into" the multiple RSS feed issue.