What would have gone down in S4?
I wonder if the writers had a decent plan for S4. I mean, you have this Human outlier force going up against some type of alien race that A, has stealth technology and B, can seemingly kill with it's mind...What possible outcome could there possibly be other than a total wipe out of Humanity.
The super OP new alien explains why the Hosts are seemingly mechanical/robots. Perhaps they had to evolve to that point so as to not be vulnerable to whatever mind melting power the new aliens have.