In previous episodes all holodeck characters had a personality of sorts, so why didn't Leah's?
Unlike those ones, this was a work-related holoprogram, not a recreational one. So maybe something broke in the programming when the holodeck was asked to impart humanity into a program that was not built to possess it. A faulty expansion pack.
Plus, where would it get said personality? From personal logs and psychological profiles, and everyone knows that how we see ourselves is not how others perceive us.
Plus, how it began is not how it ends. An imperfect extrapolation from a warmer starting point and with each successive interaction, errors build and snowball until the finished product is unrecognizable.
