Do you wish Marlon Brando accepted the lead role?
This is an interesting story, Robert Evans, who was involved with this production, sought Marlon Brando for the role. Although Marlon Brando was too old for the part, at 49, Evans wanted him in large part due to The Godfather & Last Tango In Paris reestablishing him as a box office star.
Incensed at his loss of income when he surrendered his profit participation points for $100,000 to Paramount before the release of The Godfather, Brando personally negotiated his deal, demanding an unprecedented salary reportedly as high as $4 million salary (I think for both Great Gatsby & Godfather II), frankly revealing that the high salary would recoup his losses from the sale of his points.
However, Gulf + Western CEO Charles Bludhorn, whose conglomerate owned Paramount, vetoed any such deal on the grounds that the two movies were separate entities. As a result, Brando turned down The Great Gatsby and also refused to appear in Godfather II, feeling he was being disrespected.
I think Brando would of been interesting, though too old, but I find interesting not doing this film actually resulted in him not doing his cameo in Godfather II. Ultimately, I think the film would of been the same as From what I read, the director, Jack Clayton, pretty much ignore the nuances of the script that was written. (Coppola wrote the script and everyone who read it thought it was brilliant, but Coppola said, "Not that the director paid any attention to it. The script that I wrote did not get made."
All in All, Do you wish Brando was in The 1974 adaptation of The Great Gatsby.