We actually did discuss this on these boards many years back, but I'd have no idea how to begin about searching for that thread. Especially since we have such a long history of going off on tangents, the name of the thread probably has nothing to do with that discussion at all.
I could make all sorts of arguments about how film and books are of a very different nature, and that adding modern special effects to a 20 year old movie is more like sewing a bright shinny brand new piece of fabric onto a old worn pair of pants as a patch, where it will stand out like a sore thumb, while adding and revising a few lines in a book is more like patching something with the same sort of cloth it was originally made from.
But actually, I find the revision of books extremely annoying in the exact same way I find the revision of films annoying. My annoyance on this matter doesn't stop with just the Star Wars films, I don't pick on them just to be picking on them. I actually prefer to experience all works in a way as close as possible to the original audience, books being no exception. So much so that I literally cringe every time I pick up my American printing of books like Douglas Adams' Hitchhiker's Guide to the Galaxy series and find words like "torch" replaced with "flashlight". (Honestly, Americans are not that dumb. I am sure they are perfectly capable of figuring out that Arther Dent is not actually using a burning stick in order to see while rummaging through the filing cabinet in the disused lavatory with the "Beware of the Leopard" sign on the door. Part of the charm of something like Douglas Adams books are how British they are, and by Americanizing them, we lose a bit of that.)
I can understand why Tolkien seriously revised that part of The Hobbit, and I don't really fault him for it. I feel it was done very seamlessly, and without really changing anything in the books overall storyline. But I still like to be able to read it the way it was first presented to the world. Which is why my lovely little hardcover copy of The Hobbit has a printed piece of paper containing the original chapter printed in very small font folded up and stuck behind the dust jacket.
C. S. Lewis also changed bits to his Narnia books over the years, most severe of which was the part in The Voyage of the Dawn Treader where they rescue a castaway. Honestly, I much prefer the original version of that sequence, and regret that that version is doomed to exile in only the old tattered printings of that book. But again, I can forgive this, because the whole thing, exactly as it was originally written, is readily available to the world in the same sort of quality as the replacement. Anyone who wants to read the unaltered chapter of The Hobbit or the original bit from The Voyage of the Dawn Treader only has to do a quick web search in order to do so. If I am not mistaken, the recently published History of The Hobbit, contains the unaltered parts as well.
I have said many times on these forums before, I do not begrudge Lucas just for simply changing those parts, I begrudge him for changing those parts, then going way out of his way to ensure they are never seen again... or more recently, to ensure they are never seen again in enjoyable quality.
Had C. S. Lewis, J. R. R. Tolkien, or other authors who have revised their books after the first publication displayed the same attitude as George Lucas has on the situation, then I think I'd be pretty quick to feel the same way about them as I do about Lucas.
I think another reason why this isn't brought up as much, is because of The Hobbit's age, none of us here experienced reading it one way as a child, then forced to read only the altered version thereafter.