Im not sure to be honest that I have noticed that much her mannerisms and I havent seen her in anything else to compare really. I guess its probably the story lines, but as you say its a bit boring now, the bad lady and her antics. Perhaps shes bored doing it now and needs a different challenge. LOL.
Have to say though looking around, you could say the same about most of the actors on there, that they have their character and have to stick to it. Like Shirley never changes, nor phil, or heather, or any of them really.