I would like to see some new plot complications.
I realize there's some truth to the old saw "there are only [x number] plots, and everything else is a variation." Writers understand well that the story is in the details. "Boy and girl of different social groups fall in love" covers everything from Romeo and Juliet to Grease.
But there are certain details that I don't think need to be rehashed again. #1 on my list is the romance novel trope of "boy and girl are caught in a compromising position and must wed for the sake of her reputation."
It might bother me less if the compromising position ever was actually what people will assume. Hero and heroine are caught doing the Regency equivalent of necking in the back seat of daddy's Chevy? That would be great. It would be a change.
A change from what? All the books where the hero or heroine accidentally walks in on the other while they're semi- or unclothed. It ranges from "whoops, I didn't think anyone was in here" to "she fell in the lake and I was just loosening her clothes so she can breathe." But somehow it happens all the time, and there's always some convenient gossipy type who comes along at the exact wrong moment.
This trope is usually combined with the trope where one or the other of them doesn't want to be married. Most common is the man doesn't want to get married because his former wife (sometimes dead, sometimes -gasp!- he's divorced) was a horrible person who tricked him into marriage because he's rich and oh no here we go again! with the heroine.
On occasion it's that the heroine wants to have a career (such as is available to women in the 19th c), usually as a botanist or artist or writer, and she doesn't think she can pursue this if she's tied down to a husband, even a wealthy nobleman.
I really need to invent a Regency Romance Novel bingo sheet.