DM probably wins, BUT Williams has a chance if he can drag the fight inside. Prince Charles was an excellent infighter, and infighting was DM's weakness. He depended on operating at midrange. But DM is the safer pick. He possibly stops Williams late in a grueling fight, but I'll give Williams the benefit of the doubt and say he lasts the distance.
I liked Charles Williams. In some ways I felt the parade passed him by during the years he was at his pinnacle. Fights with Jeff Harding, Virgil Hill and Dennis Andries and Don Lalonde would have been interesting. He began his career poorly managed and lost a few of his early outings. This changed when he acquired a female manager who turned his career around. As for how he’d fair against DM, I think he could give Darius a good run for his money - perhaps even pull of an upset. But I have to favor the guy who had a longer streak of success and a more consistent run... DM by decision
Might depend on the referee and the location. With an impartial referee who lets the fight flow, Williams has a good chance here based on styles. As others have said above, Michalczewski had virtually no inside game and at times seemed to get clocked with the uppercut whenever his opponent threw it. If Williams is able to get and then stay close to Michalczewski he'd probably be in command. That's not all down to the referee, of course. For all his limitations Michalczewski had a quality and heavy jab which Williams would have to navigate first. That's another reason Williams would have to get inside as often as he could, because he'd essentially be rendering Michalczewski's best punch irrelevant in the fight. Both guys really only had one way of fighting, so it would be interesting to see which one of them forces the other onto the back foot. Michalczewski obviously a bit more measured in how he pressured opponents and tended to come on late, whereas Williams was more robust and wild, and set a quicker pace before occasionally tiring later on. Maske did beat Williams, but I mention the referee here because it was very noticeable in that fight that the referee was often very quick to break them from the clinches, and that he also let Maske get away with pulling Williams' head down and shoving him off as they broke without ever losing a point (on the other hand, Williams had a point taken a little harshly, in my opinion). It's not unusual that referees do that, of course, but if it had been someone like Steve Smoger officiating then he'd have probably given them more chances to punch their way out of the clinches and allow the inside exchanges, which would have at least given Williams a better shot. I do also have to give Maske some credit, mind you, because while he wasn't a great puncher on the inside, he was physically strong there and in the clinches which were allowed, he almost always tied Williams' left up on the referee's blind side and stopped him from being as effective as he wanted to be. Michalczewski probably couldn't do that, and that might cost him the fight, hence the referee could be crucial. We all know that when a referee had a pivotal role to play in any Michalczewski fight, he tended to go in Dariusz's favour. On balance, I guess I'd probably have to edge towards Michalczewski here, as Williams needs a couple too many things to fall into place for him. None of them in isolation are too far-fetched, but the chances of them combining in his favour on one night are. Also don't want to sound too dismissive of Dariusz as a fighter, because while he had a bit of help occasionally he was a very solid championship performer. His superior boxing at mid range and his tendency to come on late in fights against Williams' slight tendency to fade mean he probably takes a very hard-fought decision more often than not. 115-113 or something thereabouts.
The uppercut is a great point. DM was a total sucker for uppercuts and Williams had an excellent one. Prince is a live underdog for sure. He had a much shorter prime than DM, but in his brief prime this probably only a 55/45 fight in favor of DM.
