It's interesting that commentators were calling it for Duran by round 12 and that Leonard needed a KO to win in the final rounds? (see Cosell)
I have never heard Leonard complain about the decision, he lost it and then tactically won post fight by receiving a rematch just 6 months later when Duran simply wasn't ready. (He blew up enormously between fights)
Duran should've forced Leonard to wait at least 12 months and had another fight before agreeing to meet again, Leonard was always going to improve after fighting someone like Duran, IMO it was the best thing that happened to Leonard, it may well have been the telling factor in the first Hearns fight when he cameback from the brink of defeat and pulled out an amazing win. You don't fight a decade long champion like Roberto Duran and not learn something. In fact it was Duran who ended up making the mistake in the end.