Since Jeyne Westerling is now Talisa, I guess that means we won't get that awesome AFFC scene where Jaime grills her about whether she's pregnant, and we find out that her mother was secretly giving her some kind of birth-control tea. That scene also had a really touching moment where she refused to give up the crown that Robb had given her. I hope they can find a way to keep that.
Funny you should mention that chapter. Jaime's description of her is quite different from Catelyn's.
pretty, undeniably, with her chestnut curls and heart-shaped face, and that shy smile. Slender, but with good hips, Catelyn noted. She would have no trouble bearing children at least."
vs.
she did not look dangerous. Jeyne was a willowy girl, no more than fifteen or sixteen, more awkward than graceful. She had narrow hips, breasts the size of apples, a mop of chestnut curls, and the soft brown eyes of a doe. Pretty enough for a child, Jaime decided, but not a girl to lose a kingdom for.
It's been speculated that Sybell is trying to pass off the younger sister, Elenya, as Jeyne. Which opens up a whole host of interesting possibilities
There's also circumstantial evidence; Sybill is angry because the Freys killed her son Raynald, Edmure seems peculiarly pleased about something and the Blackfish has vanished.