In reply to:
what exactly is the revolution that occurs in the shire?
In the book the heros run into Saruman (dressed like a beggar), and Wormtongue while on their way back to the Shire. They spare the pair. The hobbits do not go directly back, however, and by the time they get there the Shire has been overrun by thugs under the control of an unseen and unnamed person. The hobbits manage to lead a revolt which drives out the evil people, and their leader turns out to be Saruman. All this takes 75 pages or so.
I agree, the very last bit with Sam and his wife and children could have been lopped off...ending the movie with Frodo, Bilbo, and Gandalf sailing off into the sunset would have been great.
BTW, in the book all ring bearers eventually sail off to the Gray Havens, and Sam goes there (remember, he bore the ring for a while) after his wife dies.
In the book, there's literally hundreds of pages of story, epilogues and appendices after Frodo throws the ring into Mount Doom.
Mark