Is this anything?

Plot idea: it’s two years after some YA fantasy protagonist has saved the world with a magical object. Story would be a political intrigue about being exiled by her uncle and clawing her way back to power. Is this a good idea?

Sounds pretty good to me and is probably something that I'd read.

(In all honesty, it doesn't matter whether or not someone else thinks that it's a good idea as long as you do.)