The Hunger Games left big shoes to fill, after being one of the more haunting, intense and well-written books I've read. Unfortunately, the series went downhill a lot from there. Catching Fire was closer to the first in intrigue and intensity, however Mockingjay falls flat on its face many times and is cringeworthy many others.
With the intensity of the Hunger Games drama out of the way - and no way to shoehorn another games in without being even more uncomfortable - Collins has very little to work with. It's a lot of pointless relationship drama, main character self-loathing, and political drama that misses the mark. Might have been much better if not for the bar set by the first book.