Three other parts that were noticeably missing or changed were Frodo moving out of Bag End at the beginning, the Scouring of the Shire at the end, and the Field of Cormallen.
I also wished they had done the great darkness for the battle at Minas Tirith, instead of the vague overcast of the movie.
I do remember that it was a few years that Frodo had stayed in Bag End, after Bilbo had left, before Gandalf had reappeared to find that ring. This probably could have been portrayed better that it was years and not months between Bilbo’s 111th birthday and the time Gandalf returned.
I also remember the scouring of the Shire, where Saruman was going to tear down the village and how he lost the power in his voice.
I don’t offhand remember the Field of Cormallen though.