Let's put the best features forward. JEZEBEL is a superbly acted film and well directed. Both Bette Davis and Fay Bainter deserved their Oscars for their performances in the film. Davis's Julie has a remarkably blind spot about how far womens rights have gone in the age of Millard Fillmore, for it is only four years since the first womens suffrage conference was held in New York State. The most noted woman of 1853 was probably George Sand the novelist, but people thought of her as the lover of Chopin. Henry Fonda's Pres is a man of dignity and one who will not let anyone make a fool of him. George Brent as Buck represents a final flowering of the Old South's aristocracy and even chivalry (and again demonstrates that Brent could act - note the heavy restraint when he confronts Richard Cromwell's Ted toward the end of the film). Donald Crisp has a great moment telling off the cowards in the saloon in New Orleans who won't assist him with a prominent patient. William Wyler does do a first rate job of directing - as in what is an early highpoint of the film: Pres teaching Davis' Julie a lesson by humiliating her at the "Nimbus" ball for wearing a scarlet dress.
That said, why is JEZEBEL a lesser film than GONE WITH THE WIND? JEZEBEL was a film about a willful and spoiled southern belle named Julie, and how her selfishness hurts many of the people in her life. It is a great part for Davis (and probably would have been just as good for Miriam Hopkins, the one who played the role on stage). But it is not grand enough. Maybe if it concentrated on the "Yellow Fever" epidemic it could have been (but then, the 1938 audience had also seen MGM's YELLOW JACK, and was aware of how to tell the story of that scourge). GONE WITH THE WIND had a willful, spoiled heroine too, named Scarlet O'Hara, and played by Vivienne Leigh. But while she too is at the center of the story, the story is epic in describing the Civil War's affect on Atlanta and Georgia, and the slow "Reconstruction" of the economy there in the late 1860s and 1870s. As a result there was more meat in GONE WITH THE WIND (compare Fonda's genteel banker Pres with the rough and ready Rhett Butler of Clark Gable and you can see what I am talking of).
This does not diminish JEZEBEL as entertainment, even if one dislikes the stereotypes of African - Americans as incredibly loyal slaves. I somehow think the average slave in Louisiana in 1853 would have looked to their own safety in such epidemics and been rather neutral about the number of Caucasian - Americans who were carried off by the disease. But then stereotypes abound in GONE WITH THE WIND (to its detriment). But there is no character like "Mammy" (Hattie MacDaniel) in JEZEBEL, to steal the picture from the star. Actually, despite her being shown to be simple-minded, Butterfly McQueen's "Prissy" is also more memorable than her equivalents in JEZEBEL.
In the end, what can be said of JEZEBEL? An entertaining film that was well made and acted...a little out of date due to stereotypes of slaves. But it's overall significance? - it answers the question, "which was the better of the two movies that Bette Davis won the Academy Award for in the 1930s?" (the other one is the now forgotten DANGEROUS).