If Ned Racine were gay, the whole plot of "Body Heat" would have fallen apart.
What other changed single plot element would render a screenplay moot?
If Dorothy had been a bitch no one would have helped her get to see the Wizard.
OP, the plot of pretty much every rom com, love story, and drama or thriller hinging on a sexual affair, love triangle, etc, would fall apart if a main character's sexual orientation were different (but all other characters' genders and orientations were the same). This is not exactly a revelation.
R3, I think you missed the point.
If the main character's sexual orientation were changed (and the associated sex of his target for love/lust)... in many rom-coms, the same plot can play out. In some, though, the fact that it's gay instead of straight renders the entire premise invalid.
Katherine Heigl's "Knocked Up" would have been just another "The Object of My Affection" or "The Next Best Thing."
If Eve Harrington had been a heterosexual man....
If Scarlett O'Hara had been black....
If Sophie had been childless....
If Ned Racine were gay, couldn't the story still work on the basis that he's obsessed with Matty for some reason other than his lust? Diva worship, perhaps?
Mtty Walker is my fave female villain, not to mention that "Body Heat" is that rare mainstream film where the villain, at the end, actually flourishes.
Why would gay instead of straight render the whole premise of Body Heat invalid, r4? You could tell the whole story with gay men as the main characters.
If "Breaking Bad" was set in any other Western country...how Walt was going to pay for his chemo never even would have been a concern. Plot unravels.
If I was in "Albert Nobbs", somebody might've seen it.