I've complained that the first two films could both have been better if made longer, but perhaps Mockingjay shows why this doesn't always work.
On the one hand, the film is fun enough, the cast are still solid (even more so in fact, they keep having incredible actors in small roles), and it is nice to have a bit more time for character development. But almost all of that time is spent on Katniss, rather than fleshing out anything else. And you can tell that this isn't a complete story; it just slightly ends, and there's no strong narrative structure. It's a midpoint, through and through. Plus, there are quite a lot of bits which feel like they could have been streamlined (multiple trips to District 12?) or cut.
It's still fun, but two films of setup in a row is starting to weaken the overall appeal.