March should have been nominated...
...instead of Tracy.
Don't get me wrong, I love Spencer Tracy and he did an amazing job in this movie, but Tracy was playing Tracy. That was how he was in real life, according to many things that I've read.
Fredric March, on the other hand, was great in his role. It was totally unlike anything he had done before (for instance, just compare him here to him in The Best Years of our Lives or The Man in the Gray Flannel Suit). The man didn't even look like himself, for goodness' sake.
Fredric March should have received an Oscar nomination.
Gene Kelly deserved a nomination too.