For me it feels like mostly a question of the whiplash of going from limitless possibility to finite reality. [name_m]Even[/name_m] when having a new child in your arms feels like the culmination of so much dreaming and waiting and hoping, it us also a painful contraction down from a dreamed-up future as open as anything could be to one, singular, very real entity (a new entity with limitless possibilities ahead of them in turn).
Name vision and imagery certainly play an early role and a huge role in the choice itself. Yet, in getting to know the person my now toddler is becoming, I honestly have trouble recalling the expectations of his personality and behavior that I had based on his name before I gave it to him. Some people do have very specific visions though, which become expectations that may or may not be met. In the end, the names we choose say much more about ourselves as parents than about our children, but they are the ones forever stamped with our idealogies and hopes and world views through their names, which helps constantly bind them to us.
So, I think the cognitive dissonance of feeling like “Well, I really don’t like that I’m hoping for one sex over the other based solely on naming. But here I am and I do have a preference when I just don’t want this beautiful specimen of a name to go unused,” I personally feel like that dissonance and discomfort has much more to do with truly loving names than with the specific vision for the future child. But that’s just me.