I know Williams is very highly regarded here h2h, but stylistically, although he was a good ring general and had a good jab that found the range and target well, he wasnt mobile enough imo for this one. Duran would be able to fight him, and that is still not easy by any means, because that is also Williams' territory aswell as Duran's, on the inside Williams was great and had power and speed, great explosiveness in that area. But Duran is just a man i dont favour people over there, i think Duran would go to work and he could eventually, after a gruelling one early on, get his resullt.
Only seen about 4 or 5 fights of Williams, but the only thing I think he may have over Duran is speed, and even that isn't for sure. I feel Duran simply did everything better than Williams. In 15 rounds, as great as Ike was, I have to say Duran stops him late. Great action, but Duran would be ahead when the end comes.