She said she had to play that up because she no longer felt Jill was a heroine, or something along those lines. Whatever happened it seemed like things started spinning out of control somewhere between the early months or first year of her return and 1986-1987. It's a shame, since as much I do love Jess as Jill, I think Brenda at her best really got the heart and emotions of Jill (as shown in some of those '80s flashback episodes and more raw moments).
I always wondered what went on with BD and the show in her second run. What bits I saw of her 70's run, she was more human. In her 80's run (when I was watching then) she came across as a campy caricature and cheap copy of Alexis on Dynasty. At one point she started speaking with kind of a eurotrash accent.
Dickson said it was very jarring to her as she felt Jill was now being written as a villain. I always wondered because while I haven't actually seen the late '70s material I get that type of vibe from some of it.