Aye, it would be nice to be able to genetically engineer troops, I'm not sure how that would differ in effect from the "Ground Unit Strength" research. Adjusting longevity of the species via genetic enhancement would also be pretty cool, I'm actually surprised its not already in.
Genetic research could also have other effects, like increasing productivity/income/manufacturing output of a planet - like a leaders bonuses giving a small percent of enhancement, you could temper that with unrest (as in today where folks are unhappy about GM stuff).