You're incorrect. Dunne starred in the 1936 version directed by James Whale, which is a classic. The 1951 had Kathryn Grayson playing Magnolia, and Ava Gardner playing the half-black Julie, a part played by a great Helen Morgan in the 1936 version. The 1936 also has Paul Robeson singing "Ol' Man River," and Hattie McDaniel and Helen Morgan both singing "Can't Help Lovin' Dat Man".
As for Cimarron
, I've never seen it and am in even less of a hurry to see it now.