Actually, I'd say the change in her wasn't that strong, but yeah, she did change.
Basically, over the course of the game the renders were seriously upgraded and that changed the look of some of the characters.
For me, it was really charring with Monica at the start. Her face seemed so different, it felt like she was somebody else.
But in general it seemed (and again, this is just how it was for me personally, I'm not claiming objectivity when it comes to how attractive certain women are) as if the look of several of the ladies was way smoother now, more rounded, but also less distinct.
It really took three to four updates until I got over it, at least with Monica.