Kat, I think creating a genuine conflict that keeps the two MCs apart (and which they have to mutually overcome to live HEA) is extremely important and very hard to do. I would say ninety percent of the problems I see in romance stem from a poor understanding of how conflict between the two MCs works or should work.
Interesting thoughts on historicals! I don’t read many of these as I am full up on dukes and don’t understand why more royals weren’t beheaded, but that’s just me. I would like to see more exploration of the love lives of ordinary people in historical times.