But if these people died, we'd lose pretty well all the most interesting characters in the series.
Like EODO, the only character on the list that I really didn't like was Roshone. I really liked Sadeas throughout the book, and the Taravingian reveal at the end is awesome.
In fact, I can't help but like Taravingian. Here's a guy who believes in the Almighty, as evidenced by his debate with Jasnah early in the book, knows he's completely dooming himself by his actions to whatever doom these guys believe in, and yet continues his actions because he believes his saving the world. And for all we know, he might be right with what he's doing. He calls these people his dear friends, and is still willing to sacrifice them. Evil? Completely. But he might be just what the world needs at this point.
Yeah, I would much prefer a Taravingian book to a Shallan, Adolin, or another Kaladin book, but I don't think it's happening. Some characters need to remain mysterious.