"They lost their highest-usage guy, so they'll be worse" is such an easy talking point. MOST of the time it's true, because high-usage guys tend to be great relative to their competition. Corey wasn't. He got the usage he did out of necessity. It doesn't necessarily follow that a team will get worse with a player like that leaving.
Sa, Bullock, and Mensah were all zeroes offensively, and they're all gone. Doucoure was roughly as bad and his minutes look like they'll be cut. Freeman and Williams did things to help the team but they also combined to shoot under 20% on more than 100 three-point attempts. They're gone. In their place are players that, collectively, I think will make for a stronger team.
If you run last year's team back without Sanders then yes, of COURSE they'd be worse. But the math isn't "last year's team minus Sanders." It's last year's team minus Sanders and also minus six other guys who couldn't throw a beach ball in the ocean, then you ADD Kiss, Johnson, Carter, Harper, Mathis, and McConnell.