She answers almost every question within seconds.
She posts dozens of times a day.
She is in your insider group and gives you plenty of feedback.
On paper, she is your indispensable member.
And now she’s annoyed about something and wants a change.
Be careful here.
The more you treat her as the boss of a community (rather than a volunteer), the more she will behave like the boss of a community.
If the ideas and feedback are good and representative of the community, then act upon them. But don’t act upon them just because she’s your top member.
p.s. it’s often the very top user whose holding back participation from other members by responding to every question before anyone else gets a chance.