I am a fan of the Hunger Games trilogy and currently working on Mockingjay, the third and final book. I finally saw The Hunger Games in August, and while as a movie it was pretty good. But, as a adaptation of the book it was HORRIBLE! There was lack of development and nothing was explained, there was one exception. Other than that, it was horrible. It needs rebooted and here is what I would do to reboot The Hunger Games.
More character development

The only development they gave the movie was to Seneca Crane, a character you see maybe once or twice in the book and yea it was cool to see the Capitol during the games but that's it. They don't touch on anything about Katniss' dad, why she's so skilled at hunting, her relationship with Gale, the boy with the bread (we saw it, but it wasn't explained), her relationship with Peeta during the end of the games and Katniss' life as a whole in District 12. None of it was explained in the movie and it was quite frustrating. How do they expect to make Catching Fire, Mockingjay parts 1 and 2 any good if they don't develop anything in the movie and don't explain anything about Katniss, her character and the relationships she has with anybody around her. Hell, if they had just done all of that then the movie would've been a maximum of 20 minutes longer.
Lack of Explanation
As stated above, there wasn't an explanation for alot of things. They completely ignore Katniss' damaged ear, they don't amputate Peeta's leg like in the book and they don't explain why/how her dad is dead. Katniss' new ear and Peeta's new leg plays a part, a small part but a part in the Quater Quell in Catching Fire. Again, we don't get to know Katniss or why she is such an angry person.
Tone
The tone of the movie was wrong, anyone who has read the books and thinks the movie nailed the tone apparently hasn't read the books in a long time. Kevin Tancharoen's pitch for Hunger Games as far as the tone goes is much more in line with the books. It needs to be a dark, despressing atmopshere. The Hunger Games themselves need to be a scary, frightening, violent place. I thought they handeld the violence and blood fine in the movie, but they didn't have the right tone for the movie.
Look
The look of the movie needed to be brooding, district 12 needed to have a more post apocolyptic type of look. Just by looking at it, you needed to be able to tell that these people are suffering. That they are struggling. The movie that Gary Ross gave us had a more polished, new, fresh sort of look like everything is ok except for when in the games. That's at least how I looked at it.
Rating
I'm fine with a PG-13 rating, but they need to push it more. The book had the perfect balance of suspense, drama and violence. They violence and the blood that goes with it needs to be enough to barely get a PG-13 rating. Darker and more serious than The Dark Knight. The rating should reflect that this is NOT a kids movie, not a teen girl type of movie. It needs to reflect that this is a very serious, emotional, violent movie.
What I would do if I were to reboot, The Hunger Games
I would develop Katniss as she is in the book and explain everything about her, even the boy with the bread incident. Her relationships with the other characters would have more depth to it as her relationships with her sister, Gale, Rue and Peeta would be more emotional. She would have the damaged ear, Peeta would have the amputated leg, District 12 would look like a place that is suffering, the tone would be very dark, brutal and depression.
Overall: The Hunger Games was a good movie but crap adaptation. It needs to be rebooted with more character development, more serious tone and look. No, I'm not saying put everything in the movie but put the most important part of each character and put those things in the movie. It needs to be an emotional, depressing, violent movie. I cried when I read Rue's death, I could've cared less about it in the movie. There was no feeling of emotion what so ever coming from me to the movie, I could've cared less about the characters. I have lost faith in the rest of the movies until an appropriate adaptation comes out.
These are my thoughts, what are yours? Comment below and be respectful in those comments.