As I sat in the movie theater on March 20th, anticipating the Mockingjay Part 1 teaser trailer and the movie, obviously, I was thinking. I read and watched some changes departed from the book, and I was especially worried. See how well the I am Number Four, Eragon, Percy Jackson and the Olympians, etc turned out when the movies departed from the books? Obviously, Insurgent will not fail, due to the loyal fanbase of book-readers. But, I am worried now for Allegiant Part 1 and Part 2.
First, let me begin by saying this: as a movie alone, it was great. Shailene Woodley is in ever-more-control of her character, Tris, and due to the bigger budget and expanded story, we advance from crew-made sets to actual farms and settings. The plot was great, acting was great, everything was great. The special effects, the glass-"themed" shattering, explosions, and fighting was much more realistic than the first movie. But there is a missing point here.
The missing point is that the plot strays from the book. After all, this is supposed to be a book-to-movie adaption, but it feels like they chose to keep the characters (not even mentioning some significant added in ones), faction names, and a very loose plot from the book. It was saddening, really. SPOILERS: I must add, "the Box" was a good addition. Only able to be unlocked if a Divergent passes all simulations of Abnegation, Amity, Candor, Dauntless, and Erudite, it held a message for the people inside the fence. I strongly believe, however, that this was not needed. I acknowledge that Veronica Roth "approves" of the changes, but I believe that if the author thought that a certain detail was needed, she or he would include it in the books.
For the average movie watcher, this may not concern you much. For the fans of the books, you might be a little disappointed, but hey, you can always just enjoy it.