The author sounds like an idiot, but the movie sounds like shit. Humans wanting to kill Jake Sully is the only part I'd keep, if I was writing this sequel: Earth might recognise that the executive from the first movie fucked everything up when he turned the chilly relations into a hot war by bulldozing the natives' sacred sites, but there will be people who want Sully dead either as a traitor or out of the belief that normalising relations so we can go back to mining superconductors will be easier if he disappears.