The exploration of humanity is a bedrock Trek theme. I don't think any more time is spent on 7's search for her humanity than Data's.
Of course it was. However, the focus was not on humanity as a whole, but almost exclusively on one aspect thereof. It sounded to me as if the show was trying to distance itself from the humanism of TNG. Perhaps the pendulum needed to swing the other way. Regardless, the pervasive and literal references to "individuality" were as subtle as a sledgehammer.