It's an interesting fight. Pryor showed his true colors when faced with pure firepower against the likes of Arguello and even a guy like Dujuan Johnson, so I don't think Williams would force him to fight a different fight. However, he was better than either of those guys at around 135-140, and the more powerful puncher. He was also a dynamite finisher once he'd hurt an opponent. Pryor would be in his face at all times, which would lead to a lot of countering opportunities for Williams, but also a lot of opportunities to be hurt. At his best, I'd favor Williams to hurt Pryor more often than not, going to the body and head to slow him down, and possibly stopping him late. I do think Pryor had the better chin than Ike though, so it's be interesting to see how either took the others best punches. I think Pryor is capable of winning as well for sure. Basically a toss-up.
I think Ike takes it, his body punching was awesome and this would allow him to at least slow Pryor down plus due to his style Pryor was open to take a lot of shots and I feel against a finisher like Williams you'll be made to pay. Williams stops him late in the championship rounds.