Seems to me Jay Gatsby is the only character who could "want" anything: his illusion of Daisy and acceptance in "the East." Tom wants to screw around and Myrtle wants Tom, but they're not the title characters. Nick is only an observer and Daisy already has everything.
Gatsby would also deliver the qualified love song.
The 1974 movie doesn't work because visualizing Gatsby took away his mystery and appeal. Redford was no help. The Luhrmann version was a fiasco.