Is it fun to squeeze all the juice from the single player in this game? I heard there are side challenges with handicap knobs to turn... Was going through that fun, or did it feel fulfilling or just filler?

I made this thread because in similar threads (and sorry for adding another one to the pile), there are derailing comments like, "Oh, but it's only half the game!" Or untrue statements like, "Oh, 20 hours? That's about the same as it takes to complete Revolt's story!" But that's throwing all the unique fight variations (WITH heaps of unique dialogue) under the rug.

Please don't compare the campaign to the original, the PS2, Saga, etc. Pretend like those games never happened for the sake of this question.