There is
a bug that Kaz has noted in this thread, which does inflate her usefulness in some cases.
That said, while keeping in mind she's still a new character, data so far indicates she's not used overly often on defense, and when she is, she has a
stunningly low win percentage (pun intended). Like, worse than 3/4 the roster low. I could see her boosting the defense win percentages if you hang around the lowest divisions, but so would many other powerful characters.
People on the forum have discussed working around her; it's honestly not hard. She only punishes those who are not prepared, and her counters counter her hard. Her value is more in punishing certain defense when you use her as an attacker, and in certain Brave New World dungeons (absolutely tears through a lot of waves in the Garden of Life, even if she becomes a bit of a liability against the Dragon King himself).