DISCLAIMER: I have only played Siralim 1 my suggestions are based on that.
A lot of the random quests are about helping your subjects by finding resources to help the economy, gather cores for the army, recruiting citizens for your county, ect. My though was why not make that a measurable part of the game? If the people are not happy with you, you can’t expand the castle or something like that. To keep the people happy with you, you must actually sacrifice cores or resources from your inventory. That would eat up extra resources, slow game play (really its an infinite game), and add a sense of realism/progress to the monster killing grind.