The writing for Cassie under Laura's watch was often a mess, from early on - when I watch some of her Gottlieb-era material from 1991 she is ALWAYS about to have a breakdown. I can't imagine how draining that was to play.
I think that's another reason JFP assumed she could just write the character out without fans caring (and of course it was also likely a way to get rid of Robin Strasser).
I think Cassie had many valid reasons to be appalled by Dorian for Robin's first few years back in the role. After that, it started to feel forced. But this was a longrunning problem with the writing for the Cramer women, even after Cassie left.
It's around 1995 that the writing starts to fall into a rut for Cassie again after a few cohesive years. And then having her leave Andrew for Kevin just, in the long run, weakened the character, although I assume if JFP had not come in, Andrew and Cassie would have reunited.
I think that's a factor as well. I also think Rauch's horniness plays out onscreen, and I don't think a lot of viewers, who watched Cassie grow up under various actresses, felt comfortable with the more sexual take.