HONG KONG—Senior Macau casino and junket executives met with authorities in the world’s biggest gambling hub on Monday seeking details on proposed regulatory changes but received little in the way of clarity. The 70-minute meeting, shown online, highlighted the uncertainty hanging over the industry since the government kicked off a regulatory overhaul on Sept. 14. That has sent shares in the hub’s casinos plunging, especially as Macau’s lucrative casino licenses are up for rebidding next year. The meeting was the only official opportunity for the industry to air its views during the 45-day gaming consultation. It was attended by Sands China, Wynn Macau, Galaxy Entertainment, MGM China, Melco Resorts, and SJM Holdings. Macau authorities have identified nine areas of potential change including having government representatives supervise daily casino operations, the number of licenses, better regulation, and employee welfare. During the meeting, industry executives agreed that Macau’s 20-year gaming law needs …