Guys,
If this series continues, and I'm not 100 sure that it should, Ciri is the only logical way forward. What made the Witcher cool in the first place was the attention that they paid to the source material. To have a random Witcher protagonist would just detach it from the story arc too much. The things that makes character interactions in The Wild Hunt so good is that the characters have so much history with each other, history that was created by not only CDPR but Sapkowski. In the case of Ciri they can keep playing with that formula.
If they reset the character structure completely they will have to accomplish the most amazing feat in the history of video game writing Carrying the story forward with Ciri will allow them to keep taking advantage of the character structure and keep the events in the same "orbit". Considering the amount of great secondary characters that they have, anything too drastic just doesn't make sense
Besides, it could be the first game where the female protagonist i really multi-dimensional and "real". I thought the new Tomb raider would go tthat way but half way through the plot they decided to make Lara in the typical helpless crybaby (OH NO, Captains dead , BOOHOO)