I think Ann represents Ttrick's mistake. Ann went from nerd girl who knew nothing about sex to Vanessa's level of slutiness in a matter of days. Her corruption went too fast and is not “realistic”. She's basically a doormat.
I play my main save by following the Ann hate route, as I enjoy her instantly turning into a cocksucker after being rejected, and later shamelessly trying to make you jealous and grab your attention. The cherry on the cake would be to have the option to actually tell her that to her face. To stop embarrassing herself.
I really hope that with Emily, or Alex, the corruption won't be that easy.