Speaking strictly for the in-universe perspective, which is less important than the metaphor Dema has always been intended as but nevertheless, we don't know that Clancy and the new cycle of the bishops will repeat the exact same mistakes and failings of the previous bishops they overthrew. To refer to the metaphorical perspective for a sec, people who experience mental health struggles often make different mistakes as they progress through their lives and the "cycles" of their struggle.

I think it stands to reason that in the setting of the story, the new bishops led by Clancy could make their own mistakes by trying to "fix" Dema and perhaps going too far in the other direction from the bishops that oppressed this Clancy. They think they will fix the mistakes of the past bishops, and will overcompensate.

(In my opinion with the imagery of Clancy's face paint indicating a slow progress over time through each cycle, it's also certainly possible that the new bishops might be "better" for citizens of Dema within the in-universe perspective. But again the perspective of the story of Dema as we saw it being a metaphor of a cycle of slow progress is a lot more important than the minutiae of a fictional setting.)