Was Ciri: Nova a mistake?
I can't help but feel that Ciri: Nova being a neutral was a big error. It isn't necessarily that she's available to all decks that's the issue, it's that she's so powerful that she pushes out a lot of faction golds just by virtue of being so powerful. That gives us 45 pt SK bears on round 3, 50 point NG if they use Tibor, and all kinds of other potential craziness. Her raw power is so high, and two bronzes isn't much of a sacrifice to get it, that it's kind of hard to justify not including her now that decks are so reliable.
My feeling is that neutrals should never be power golds, but tech cards like the Geralt and other witcher character golds. They have powerful effects and they do interesting things (avallac'h as well, Villentretenmerth) so they're worth looking at, but not so powerful that you look at them and build your deck around them. Ciri: Nova feels kind of overwhelming, like you either run her or lose to her.
I could be wrong, but aside from Avallac'h and mill, I can't think of another neutral that people literally built their decks around. Villen was an auto-include sometimes due to gold immunity/double scorch, and gigni is an eternal presence because of his occasional ability to do monstrous things, but I feel like Ciri: Nova is something different, and not in a good way.