Tolkein has Shelob in the end of the 2nd book, and it ends with the reader supposed to think Frodo is dead, for a bit of a cliffhanger.
Jackson is obviously intending to have Shelob in the first part of the 3rd movie, in a bit of directorial re-pacing.
I liked the Movie Ents but I wanted to see Pippin & Merry sitting around drinking Ent draughts and Smoking Pipeweed in the ruins of Orthanc, and I think that is one of the cut scenes!
Just talking about this is reactivating suppressed memories - shit, soon I will be able to recall Dungeons & Dragons trivia like how many Hit Dice a Type VI Demon has or what you should do if confronted by a Giant