This movie forces you to deeply think about the subtle differences between life, intelligence, and humanity plus the ethics of forced evolution and what might (or might not) justify it.
Yes, there are plot holes, starting with why Titan in the first place, but that is beside the point. The underlying theme is not Titan at all - heck it could be Kepler 452b. The reality is that humans, with our current physical limitations, are stuck on this rocky planet, orbiting the Goldilocks zone of an average-sized Type G star. Even time in the ISS wrecks havoc on physique through muscular and bone dystrophy.
What sort of major paradigm shift do we have to go through, if we're forced to leave our home planet...or perish?! How many of us could survive the ordeal? And at what cost? Will we be able to give up our humanity and become an alien intelligence, shunned by all, even our loved ones? Is this what it means to be different and more adapted for change...giving up humanity?
I LOVED this movie, particularly since I interact with gifted children with ASD. The last scene, Rick unable to talk but perfectly suited for living on Titan, struck me as unusually powerful - here is a being that has been made to evolve and has capabilities that one cannot comprehend anymore and is PERFECT...for the right environment...