It's not like Sam is fantastic anyway, but he was a needed source of authority. Sam's biggest flaw imo was that if he wasn't feeling it for the day, he would bring the show down with him. So long as he was energetic and clearly passionate about what he was doing, the show would thrive. But you can't have a host who is checked out. A major problem with every season is the line between contestant and production fading and the fish growing disinterested because of that. Sam was sometimes a catalyst towards this bad outcome.
I think a lot of Fish, with a few exceptions, subconsciously look to the host as a behavior gauge. If the host is high energy and selling gaslights the fish will follow his direction, now more likely to become active without as much prodding. But the moment Sam stops caring it destroys any illusion of authority prod has, and the fish just stop caring as well. If prod fails to maintain their illusion of authority the show breaks and content stalls.
Sam had problems maintaining his emotions. So the show has a chance to upgrade right now to a more consistently stable host. Not sure if they're competent enough though.