I remember my fifth form (Year 11) English class well for this very reason. Our film study topic was on Gattaca, in which a major premise was on the differences in class between those who were "normal" and those who were "altered".
Naturally the altering cost a huge amount, and naturally the altered children were far superior to the nonaltered, notably brothers. And naturally there arose quite substantial differentation between the two classes, to the point that "Godchildren" (normal, unaltered, depending on God for their alleles) were unable to get jobs requiring any decent amount of intellectual or physical capability, relegating them to things like janitorial work and garbage collection.
And I think that's not far off the most probable outcome.
You raise an excellent point about the patenting of new alleles, too. Developing one that enables a person to speed up their metabolism or the rate at which toxins can be cleared from the body or a better oxygen-transporting molecule for the blood. Just think of the lawsuits that might occur should such be patented, then arise as a novel mutation somewhere down the line. Some major alteration to relevant laws might be necessary by then.
The highly intelligent kids of average parents is already a difficult situation for those parents. SuperKids probably won't find their situation easy
Ah, but if your parents were superkids themselves, both physically as well as mentally, then you have no problem. You get the typical portrayal of upper-class people being the norm: all of them are "perfect" people. Takes a couple of generations to get to that stage, of course, and the ones who get in early will have the advantage to begin with.
Any greater good will probably not be the basis of choices for engineering of offspring and probably face criticism for attempting to engage in social engineering; more likely health, looks and advantageous ability for those individuals - allowing them to better compete and dominate - will dominate the choices
A quirk of human nature, there: we abhor any attempt to make everybody better, but if you only want good for yourself then it's the done thing and you're part of the pop trend.
And then, what happens when everybody is equally good looking and intelligent and athletic? There's surely a limit to the malleability of genetics and human nature (I believe that was part of a major philosophy in the early 20th century; Marxism held the opposite view -- infinite malleability if human nature -- IIRC).