What if Eclipsa isn't the big bad that everyone thinks she is, but her presence causes a conflict in terms of succession?
It's a longshot but it was never stated she exactly abdicated her power. She got crystalized and power transferred to the next person. What if she tries to get her successor onto the throne (perhaps it's Miss Heinous) and that's the issue. She's not evil but the conflict will be something related to a political power struggle?