Some of the most appealing fanfiction to me is fanfiction for period romance dramas or stories that re-imagines the story with more societal conflict, or rather different conflict. This also applies to screen adaptations of books and such.
As interesting (and I mean that in as much as I find it interesting only for the alight conflict it brings to the story and nothing more) as Lizzy and Darcy's class disparity is, the fic that speaks outright of why such a disparity is absurd is even better. Or, while Georgiana's near elopement adds a fraught element to the story, a criticism of the idea that keeping women ignorant of sex does not prevent them from having it, but rather prevents them from a) participating safely and b)understanding what is happening so as to be able to at least attempt to put a stop to it should they so desire. Yes, Darcy's wealth is appealing as a means of sure comfort, and the praise of his housekeeper is a boon to his character, but a fic thst shows he treats his tenants exceptionally well and is an incredibly charitable man who lives well within his means so as to be able to aid those who need it? Well, that is simply much more to my interest.
I loved Anne of Green Gables as a child, but the screen adaptation Anne with an "E" brings much more into it with the addition of a queer character finding comfort and joy in his friendship with Anne, as well as the depictions of the current events of the time that take away from the romance we often find the Era of a period drama brings such as ensuring that the reality of indigenous children and residential schools be shown in a story that would otherwise not have cared.
Anyways, I like when the romance of a past era, or the supposed goodness of a character within the romance and story, is given credence by the often undiscussed aspects of those past eras.