You know, it's sad how many of my posts start that way...

The issue is that evolution is a chaotic process, and there is no real way to tell (as yet) what traits are connected to other important traits, and there will never be a way to tell what traits will be the most useful as the world changes.

"Designer people" will result in the same thing as designer field corn or highly-bred dogs. A crop that may have useful and productive traits, but must be endlessly protected against nature itself. If left alone, many agricultural species would be extinct in a single lifetime. Dogs left to themselves end up a breed of sturdy mutts.

I don't think humanity should breed itself into a hothouse plant, no matter how cool the traits are. The human animal in its current amazingly varied form has conquered almost every land environment on the planet. That's not a bad thing to have on one's evolutionary resume.