Liz has some problems in her writing especially when it comes to how she views sex. In one scene she shuts down people who try to flirt with her, on the other scene she talks about her boyfriend problems, and in the NTR route she says that sex means nothing to her.
So basically, what's all the drama for when she seems like she doesn't really give a crap about sex anyway? I understand why people dislike her. She feels a bit gimmicky.
Personally she works well for me and I rate her fairly high in my list, but that's because I think she isn't meant to be taken at face value. I won't go into detail on that, the short of it is that I like her development (assuming romance route) and where her head's at, but I flat out ignore her when she tries to "explain" things.