So I was under the impression that Genetic Engineering was forbidden by Starfleet. Not just "please don't do it". More like, we will put you in prison FOREVER. And yet, no one seems shocked when they find out what's going on at the Darwin Colony.
Deep Space Nine has several genetically engineered characters. All of them are either in prison or hiding from the law. On Enterprise, they make it very clear that genetic engineering is illegal. Sure, those shows all were written long after this episode. But at the very least, I'd expect the writers should have remembered Space Seed and Khan and made at least some reference to genetic engineering being illegal / morally questionable / frowned upon. At least some mention of a major historical issue in the Star Trek universe.
It also seems odd that you'd name the colony after Darwin. Genetic Engineering seems a bit antithetical to his research.
The Transporter hijinks at the end are absolutely ridiculous. If you can do what they did, there are a variety of unintended things you can do. Send Doctor McCoy through the Transporter using DNA from 40 years ago. Suddenly, he's young again. Somebody gets sick, just send them through using pre-illness DNA. Someone dies, send their body through using pre-death DNA. Picard gets stabbed in the heart by another Nausicaan, send him through using DNA from when he first joined Starfleet Academy. Now he's 20 and has no heart problems at all.
It was still a good episode. Though because of my near-hatred for Pulaski, I couldn't give it a good score.