So on the one hand, Data was built with certain limitations (inability to use contractions, no emotions originally, being very restricted originally in understanding informal communications and social interaction, etc). and it seems to have been the Soong's intention that he'd gradually acquire more such "human-like" abilities. It also seems he was built with the ability to emulate certain human peculiarities (e.g. dreaming, tear ducts to be able to cry), and possibly even with the ability to develop typically human imperfections (such as neuroses) to make him as close to human as possible.
On the other hand, Data had all kinds of superhuman abilities right from the start (for example strength, speed of computation, perfect memory, no need for life support, etc) that would never make him "as close to human as possible". Had that really been Soong's goal, why didn't he give Data (for example) a human-like imperfect memory? So, what exactly was it that Soong was actually aiming for? An superhuman android that wouldn't make humans around him feel uncomfortable? Something else?
On the other hand, Data had all kinds of superhuman abilities right from the start (for example strength, speed of computation, perfect memory, no need for life support, etc) that would never make him "as close to human as possible". Had that really been Soong's goal, why didn't he give Data (for example) a human-like imperfect memory? So, what exactly was it that Soong was actually aiming for? An superhuman android that wouldn't make humans around him feel uncomfortable? Something else?