I assume npcs in the missions would need the realism of reacting if you aggro enemies into their vicinity? and that requires time and money to code, but what about npcs like a thief with quests for the player who can disappear in a puff of smoke? or a genie who comes out of a lamp? 3 lamps spread out across the dungeons each granting a wish but one wish has negative consequences.
I know those where very generic ideas but surely otherside could come up with better ideas. I don’t need a token npc each dungeon floor but a few familiar faces to bump into and a few mysteries surrounding whether they are friend or foe would greatly enhance the atmosphere.