That 1974 production also benefitted from Williams' final script (which, despite arguably being not at his best by that time is one of the few times I think his final rewrite of one of his works was an improvement).
Why would Scarlet be slightly too young? She's not too much younger than Bel Geddes was in the original production, I believe.
"The gods who nurse this universe think little of mortals' cares. They sit in crowds on exclusive clouds and laugh at our love affairs. I might have had a real romance if they'd given me a chance. I loved him, but he didn't love me. I wanted him, but he didn't want me. Then the gods had a spree and indulged in another whim. Now he loves me, but I don't love him." - Cole Porter