Somehow I like the idea of bilbo doing more in the battle as long as PJ doesn't overdo it. (such as bilbo kills every goblin himself )

On the other hand going invisible and trying to stay out of harms way is as hobbit like a behaviour as it gets

Yes, I agree and that is my worry. I confess I quite liked the movies, but then I had not read the books at that time. It was after that that I was given them, all- I was swamped and I settled down over the next months to read and reread and research and study up on all that I could find about the man and his work, and his work by itself. And of course I was dismayed at more than a little of the movie material. I realized that in reality it is quite impossible to put everything from a book into a movie, and sometimes even the way something is written does not lend itself to the big screen-but I failed to understand how PJ could insert things such as Haldir and all he went through until he was killed, none of that occurred.  And attributing what one person said to another, I failed to understand how that is either necessary or right. I realize that a producer has to have his or her own interpretation of a material, but I also feel that writing is like giving birth-first you have to work with a germ of an idea, then it begins to grow and you go through a lot to bring it to the final words, to bring it out in the open to the world. And I just resent others deciding for an author how things should go. It did not come from anyone's mind except that of the author and i think it should have the integrity of that. Some of the works put on the screen of Sherlock Holmes, or Jane Austen you can actually read right along, the words are all there just as written practically. To me that is what makes them truly come alive. Being a writer myself I appreciate if the publisher says' look this part does nothing for me, rewrite it and let's see where we go from there' rather than just having him or her do the rewrite so that I cannot recognize the piece as being mine. I find that offensive.  So, I agree that with today's modern stellar sound and visual effects one can take just a piece of the Hobbit and run with it to make it a block buster of exciting adventure, if it is not really true to the book, I shall feel very cheated and angry for the Professor.