Why concentrate on the 'macabre' elements of this film?
I admit, films like this - where the star died before production ended - prompt a certain amount of morbid curiosity (Natalie Wood in "Brainstorm" also comes to mind), but Saratoga has SO many other attributes, that I get a little impatient with viewers who downgrade the film because of the "double" scenes. Sure, they're awkward and obvious (although Mary Dees, in that long shot of the "tin cup" scene with Cliff Edwards, sure looks like Harlow!) - but we should all be glad MGM finished the film, because it preserved one last performance from this beloved actress. All the performers are great - Gable at his prime, dashing Walter Pidgeon, Barrymore and Frank Morgan providing some nice comic moments, fine support from Hattie McDaniel, Margaret Hamilton, Cliff Edwards and Una Merkel. I particularly enjoy the snappy dialog, which shows the talented hand of Anita Loos.
I've read that it was a sad and disquieting experience for the cast to complete the film with a double standing in for their late departed friend and colleague. But they did the work like the pros they were - 70 years ago - so let's not mar their efforts today with excessive hand-wringing.
One imdb reviewer pointed out that Jonathan Hale, who played Frank Clayton, committed suicide...but so did Clara Blandick of "Wizard of Oz", Douglas McPhail from "Babes in Arms" and Richard Quine of "Babes on Broadway" - among others. It's sad how things turned out for these actors, but should it overshadow the merit of their performances?
I say: Just enjoy Saratoga for the late-30s era MGM film that it is. Yes, it's bittersweet at times but, at the risk of being presumptuous, I think Harlow herself would want people to enjoy the movie as a fun romp, which it is - if you let it.