"It's hard to believe that if these allegations check out — and there are dozens of them — that he can survive this," said Sonnenfeld, senior associate dean at Yale School of Management.
If he doesn't survive, that could spell trouble, because there is no bench of potential successors, Sonnenfeld told "Power Lunch."
He pinned the blame for that on Wynn's "terrible" board.
"This board was asleep at the switch," Sonnenfeld said. "How come investors don't know what's going on in terms of a succession plan? The bench strength is of major concern."
He added, "This is a very talented guy and an eponymous company with his signature, not just his name, his signature as the logo for the company. … It's very distressing."
In statements, Wynn denied he had ever assaulted anyone, calling the idea "preposterous." His company said the newspaper report reflects allegations made in court by his ex-wife "in her legal battle with him and the company."
Wynn Resorts would not comment specifically on Sonnenfeld's remarks about the board.
For his part, Sonnenfeld said he was concerned about the timing of the allegations.
"This is not to exonerate Wynn whatsoever, but you wonder why this is triggered now," he said. "You've got to be suspicious that this is motivated for some reason. The company is on a high. The stock price has doubled over last year."
— CNBC's Contessa Brewer and Michael Sheetz contributed to this report.