As I move through, I can agree about the writing vs content thing. Why have it be so dark and then leave the way everyone carries themselves to be so much like a kids show where everyone is openly declaring their conflicting mission objectives to set up fights and shit? I mean, compare to other things with similar worlds, like FFT or Vagrant Story. The characters in those games were in similarly serious worlds, but they were inside of it like real people with complexities of both personality and roles. This is kind of like Voltron characters trying to play out Gundam scenarios.
Edit: To be more specific, even without more complex roles, the responses characters have to each other could be a lot more interesting. Evil psychopath? They just take a principled stand against them every time. No sass, despite there being so much room for sass. Similarly, when someone goes on being a total perv? Let's all do the childlike "omg~ -_-" response. I guess Persona is a good comparable example of how lighthearted characters in dark situations can work out in far more convincing and clever ways, although I think even Lunar did far better in traditional scenarios closer to this game.