Aren't most of the Aliens basically bred to their genetic maximum before being augmented ?
Some things may also be mutually exclusive. Is it possible for a strongman competitor to also be as flexible as a gymnast? Seriously, I'm asking, because I don't know.
But the aliens' genetic and cybernetic augmentation also mean that they're highly adaptable. I've always dreamed of the aliens (AND their equipment, UFO's, etc) being randomly generated. Maybe they counter your increased use of plasma to higher resistances to it and new, different weapon types. It would really make autopsies useful again to anyone who's played the game before and now only does them for the points when there's no longer any useful technology to unlock, plus keeping a pool of scientists necessary past the first quarter or two.
