Romance canon, such as Romeo and Juliet or Beauty and the Beast, are used as inspiration because of the stories' integral depictions of love. They are allegories or "formulas" that our culture has almost unanimously but silently agreed on.
When the hero's former lover/mate/wife died, making him leery of falling in love with the heroine. He doesn't want to suffer the pangs of love and/or loss and/or betrayal again.
Dragons in fiction have evolved in the way of vampires, supernatural villains that once threatened and preyed upon maidens have become the heroes of paranormal romance. While a fantasy realm might seem like a draconian hero's natural habitat, there's an abundance of shapeshifting dragon aliens. What's up with that?
When the heroine has scars—indicative of a brutal backstory—which she considers disfiguring and the hero assures her are a testament of her strength.
When a writer creates a hero that's too many things, she has to fill the reader's expectations for that hero, plot-wise and romance-wise. Juggling too many and fitting them all in one book is difficult—though not impossible—and makes the story and the hero seem over the top.
Reversing or confounding mental invasion in vampire romances indicates significant change to the archetype. In monster theory, one of the vampire's greatest weapons is the ability to penetrate personal sanctums/the mind.
Bless their hearts, whatever they were thinking, including all the guys with the next "Great American Novel," they didn't laugh. And damn it, the number of people who read the genre gives the concept validity. Explaining the concepts to those unfamiliar with the genre, standing up for them, has made me take a harder look at the common core of paranormal romance.
But I am struck by the number of paranormal and urban fantasy books featuring a heroine who has vowed or neglected her magic at the start, and must come to terms with her powers in order to "save the day" or to embrace who their true identities.
When a hero/heroine's friend, who has been mourning their dead partner/mate/etc., discovers they've been alive all this time! *Cue the sequel*