The premise of the show was just implausible to begin with
It certainly had to deal with some handicaps, and Francesca suffered the most from it.
She was pregnant when Philip died and she felt uncomfortable living with the Colby family so she went back to her parents (couldn't be her mother because she still lived in England).
She and Jeff lived there for three years, that's when Cecil came to visit her.
Apparently Philip had died before he came into his inheritance, there was no money at all. Cecil had no children and he offered Francesca to make Jeff his heir, and she accepted.
But, unlike Alexis, she never really had a good reason
not to visit him unless that was part of Cecil's bargain, but they didn't mention that.
So I don't really understand why people keep saying that she was supposed to be the new Krystle when she was already such a flawed character from the very beginning.
She didn't fail as a saint because she never was.
But I think this is just what some fans had anticipated: Dynasty II, two women - oh then it
must be a Krystle and Alexis clone.
No it isn't, because this is a
different story, and that's raison d'être enough for me.
Another
The Colbys aspect that's been largely overlooked is that Jason has had a life-changing experience: he thought he was going to die.
In episode 5 he talks to Francesca about his life, and all the things that matter to him.
J: "But Sable loves the prizes, maybe that's where I lost her".
F: "It takes two to kill a marriage Jason, you can still save this one if you try. You've got your life back, think of how much of it is invested in this marriage. Do you really want to throw it all away?"
And then some episodes later, when she and Jason can no longer hide their feelings for eachother she decides to move back to London.