Now then, it has been about 25 years since I last read the book and my memory is a bit fuzzy about details, but I don't recall the book being all that different from the movie back then. It's certainly not something like The Running Man or I Robot where the only thing the books share with the movies are the names of some of the characters. The differences I recall between the book and the 1972 movie are as follows. . .
1. At the end of the movie, Willy Wonka assures Charlie that the other kids will return to their original lives unharmed. At the end of the book, from Wonka's office window Charlie sees the children leaving the chocolate factory all twisted up, covered in trash, etc. as a result of their misdeeds.Frankly, I think this is a case of screenwriters fixing mistakes in the author's narrative. Charlie is supposedly the most kind-hearted of all children, yet the book has him blithely shrugging when he sees his pals permanently harmed for their foolishness. It recalls the whole dilemma of the moral man who goes to heaven but finds only sorrow there because he knows that others are suffering proportional to his reward.
In order for Charlie to truly be the most kind-hearted boy of all, he would certainly have condemned Willy Wonka for harming his friends, so the screenwriters chose to have the children repaired and returned to their old lives "a little wiser" and without a lifetime supply of chocolate, which greatly softens the ethical contradiction at the end.
2. In the movie, the Oompa Loompas are singing orange-skinned dwarves rescued from LoompaLand. In the book, the Oompa Loompas are 3,000 black-skinned pygmies that were imported from "the very deepest and darkest part of the African jungle where no white man had been before".Yeah. I'm certain that they'll be returning the whole slavery aspect of the story to the new movie
3. The movie had songs in it. The book didn't.Big whoop. The Lord of the Rings books had songs in 'em that didn't make it into the movie. Go complain about that.
In short, the new Charlie And The Chocolate Factory will do exactly squat towards realizing the author's "vision" for the material. Given that it's being done by the man who single handedly killed any chance for Planet of the Apes to return as a franchise, my best hope is that it'll be an easily-forgotten trifle, like Return to Oz.
. . .and yeah, I do think to hard about some things. What of it?