On the other hand, humans are the apex predator of the known universe, the output of 4.5 billion years of evolution driven by relentless, unceasing violence. It's not clear that a genetically improved species would abhor violence.
Bold claim.
But I also have to preach some caution about meddling with human genetics. At this point we have what I think you can agree is a relatively poor understanding of the potential consequences of splicing DNA in a human zygote. Crashing headlong into an age of careless modifications could be disastrous for the survival of the species.
I just finished reading the Firefall duology by Peter Watts (http://rifters.com/) and one of the themes in the second book is that "baseline" humans are in some ways hardier than modified transhumans. Natural selection has fixed a lot of the bugs in us baselines over millions of years, and that's a hard-won legacy that we shouldn't be too quick to discard for barely-understood alterations.