After some study on the matter over these last many years I have come to the very ungenerous conclusion that the only really truly very good thing about FDR is that he died.
He was made into an icon for the Depression era people. My elders simply loved him. Especially my mother. Dad, not so much.
And he's bio-degradable, so there's that.
Contrast that with America's dithering since 1945. Korea, Vietnam, the Gulf wars, Afghanistan.
So I give credit where credit is due. FDR was not a perfect wartime leader. But he was a very good one.