@Thenomain - Yen's personality in the games is pretty much spot-on; it's just the appearance that's different from the books. (In the games she is older in appearance and more conventionally attractive.) The one thing they got wrong in the games for her personality is that Yen and Ciri should be as close as Geralt and Ciri, and that relationship didn't come through as well as it could have. Yen is really as much a mother to Ciri as Geralt is a father.
There's other little stuff. Book!Geralt's a bit more emo and wracked with self-doubt in places, for instance. ("Am I fucking up Ciri's destiny?" I mean, yes? But that is not a bad thing? Because her destiny kind of sucks?)
The one in the games who deviates the most is really Ciri; by Lady of the Lake she was a sarcastic and broken teenager, kind of borderline cruel at times, but she sure as hell didn't lack in confidence. (When I compare her to Arya Stark, I'm not kidding; Arya can't have inspired the character given the two pre-saga story collections and the first two Blood of Elves saga books were out in Polish before ASoIaF was published at all, but it's a frighteningly accurate analogy in places.)
That said, the shit she went through in faerie (how did she restrain herself from beating the living snot out of Avallac'h when she meets him again?!) followed by being lost for 5+ years in an entirely different world, along with not being a kid any longer, could have changed her a bit by the time she makes it home to her own world again in Witcher 3.