I think anyone expecting Dany's dragons to straight up annihilate the white walkers are in for a rude awakening. It would just be way too easy.
But besides that, when Dany arrives in Kings Landing and talks with Cersci (assuming Jamie hasn't executed her and that Dany even gives anyone time to explain themselves before commanding Dracaras) do you think she'll throw the incest in Cersi's face and shame her for it and label her a heretic? It would be quite ironic as Targs are known to intermarry and it was actually a part of their political system. But Dany was abused by her brother, both sexually and then sold off to slavery to be used as a pawn, so it would be amazing to see a Targaryn who everyone knows are incestuous, lamblasting a Lanister, who might be openly displaying her incestual ways. I mean she stopped the sparrows, killed all of the lords and such, there really is nothing to stop her from marrying Jamie, and proclaiming him king reagant or hand of the queen. Except for Qyburn is hand of the queen. New rule: There can be two hands! (I dont think Jamie wants that or anything from the mad queen) but shes deluded and stupid, so her sense of perception is all warped.
It would just be hilarious to me that Dany comes, points out that Cersi is a self professed brother fucker who has no rights to the throne, in front of a public audience and the small folk take Dany's side and rebel against Lannisters without Dany having to use a thread of violence.