I just finished running more than 400 hours of Kingmaker with a character taking the Harrow ritual that provides even more reroll options. As the party got more an more rerolls the game felt more an more flat and somewhat boring. I think the rerolls really took away the up and down story beats. Made me realize how important failed rolls are to interesting narrative.
Thinking back on my favorite moments as a player, they were often the highs following a string of great rolls, but they felt that way because the took us out of a dire situation, lost cause, or other low beat.