I really liked Kate Lockley. At first, when I watched Season One, I thought she was supposed to be the new love interest for Angel. . . but, she started to become more of a character, and I really liked her.
Yet, I didn't like how Joss just kinda, faded her out. She just sort of, dissapeared from the show. It was weird. I thought her character could've had alot more potential, but I agree, I was expecting her to come back in Season Five actually.
She found out Angel worked for Wolfram and Hart, and wanted to give him a big "told you so you're an evil loser" speech.
I was kind of dissapointed she never came back. **Shrugs**. It was weeeeeird.