Not really an original idea but how about this? Movies like
Independence Day and
War of the Worlds are based on the re-used extraterrestrial aliens wanting to displace the entire human species. Been there. Done that. How about a reversal? Sure,
Avatar had humans killing indigenous super tall blue (and nearly nude) people but they would have left the native population alone if their existence did not interfere with their mining operations (nothing spells lack of compassion like g-r-e-e-d).
How about a movie where humans are carrying out planet-wide genocide, and winning without any real opposition from the native alien population, for the simple reason of taking sole possession of their world? There was a good but simple animated movie called
Battle For Terra where humans left a dying Earth for a new world. Humans, making the voyage in slowly malfunctioning spaceships, found the world inhabited and the military decided it was an Us or Them scenario.
The natives lived in an atmosphere almost devoid of oxygen. Humans had technology that could produce oxygen on a global scale. The military attempted to use the technology and would have wiped out everybody on the planet if not for the combined efforts of an empathic male human and a curious female native teaming up (this was a PG movie for anyone getting the wrong idea
). Let the proposed movie be devoid of any empathic humans and let the worldwide survival of the fittest ensue!
~insert loud diabolical laughter here~