Was Lucy ever intended to become a long-term cast member in the Big Bang Theory? She seems to me to be a more interesting character than Emily, who replaced her as Raj's girlfriend. Have the producers ever commented on why she was written out?

Was Lucy (Kate Micucci) ever intended to become a long-term cast member in the Big Bang Theory? She seems to me to be a more interesting character than Emily, who replaced her as Raj's girlfriend. Have the producers ever commented on why she was written out?