The "scouring of Hobbiton" - a phrase I've just now learned, since I've never read the books - is portrayed by Galadriel in the movie as a "vision of something that might be".    Since I wasn't expecting a "scouring of Hobbiton", I wasn't disappointed by the lack of one in the movie.  Instead, I just take Galadriel's warning at face value - it's something that could have happened if Sauron hadn't been defeated. 

The book may have handled it differently, but in the movie, that's Frodo's prime motivation for doing what he does - he's hoping to prevent something terrible happening to the Shire. 

If the movie had ended with the Hobbits coming home to a devastated Shire after all they'd been through, well that sounds like a hella depressing way to end a movie.    Especially after watching half a dozen civilizations be almost wiped out already.   

I thought the gray havens ending gave a similar vibe to what you're describing, although it plays out exactly the opposite.  Frodo saves Hobbiton, but the experience changed him so greatly that he himself couldn't go back to his former life.    As a "cost of war" message, I thought it worked just fine.

Saruman doesn't die on-camera in the theatrical version, but Wormtongue does him in in the Extended version.