Jennifer Lawrence was miscast.
Lawrence can be very good, but she's at her best playing open, energetic, even mouthy characters, while Katniss Everdeen is quiet and never shows her feelings if she can help it. Some actors can keep quiet and let the camera read their feelings in their eyes (like Sophie Turner on "Game of "Thrones"), but Lawrence doesn't do that in these films. instead, she comes across as tough, but kind of lifeless, as we can't see Katniss's inner life in her face or eyes.
I don't know who would have been better in the role, the only actress of the right age I can think of who might be better is Shailene Woodley, who has an expressive face and melting eyes and who had to settle for the inferior "Divergent" series. She's also a big strong gal who'd be convincing as a competitor, she might have worked.