Then you get into Iain Banks' The Culture where every citizen is basically an artificial creation. I have no problem with any specific solution to our societal problems, I take issue with their externalities.
Regarding your proposed gene therapy, would this gene therapy be available to anyone? Could it be refused? Is it reversible? Who would pay for it? The beauty of The Culture is that it is not monolithic, has no border, has godlike AI that takes care of all the problems, and can be abandoned or joined by anyone.
I think we are quite a bit away from that future, but I can understand the concern and moral hazard, the future is hard to predict. In the near term, if we can fix this specific reward and metabolic pathway with gene therapy, the therapy is safe, and can be made broadly available, I think it should be done.
Regarding your proposed gene therapy, would this gene therapy be available to anyone? Could it be refused? Is it reversible? Who would pay for it? The beauty of The Culture is that it is not monolithic, has no border, has godlike AI that takes care of all the problems, and can be abandoned or joined by anyone.