In another group’s game (It’s Critical Role. You should totally watch it.), the party was assigned to kill a monster in the sewers. It was a giant spider, and its lair contained many cocooned victims. The party saved the living victim, searched the dead victims for valuable items, then left with the spider’s carcass. Their contract was to kill the creature, so their job was done.
But another group in another game could do something else with the same situation. Each of those cocooned victims was a person with a story and a family, and the party could provide endings for those stories and closure for those families.
Immediately a host of challenges emerge. Will the party carry the bodies away, or invite people into the sewers to collect them? Who is going to let a group of mercenaries store a dozen bodies for an indeterminate period? Is it somehow illegal to possess dead bodies? How can a body be identified without state-issued ID or a mobile phone? Why were these people in the sewer instead on the street above like sensible folk? Will Speak With Dead trivialize this whole affair? How will someone react when a group of heavily-armed strangers shows up with the corpse of a loved one? Will the party attend the funeral?
Some of the victims may be connected to the underworld, using the sewers to move without attracting the law’s attention. The party may find itself with unexpected entanglements, valuable connections, or new targets, depending on their opinion of organized crime.
Maybe the spider was able to snatch some people because they were forced to live in the sewers by circumstances. The party could find the surviving members of that subterranean community and either improve their makeshift homes, or fight to bring them back above ground. Living in the sewer seems pretty bad, but maybe they like it down here.
An identifying possession (an engraved pocket watch, or a military jacket with unit insignia) was stolen, pawned, or gambled away, and the corpse found with it is not the original owner. How will the friends and family of the living owner react to convincing evidence of his death?
If a victim is a wanderer (like most player characters are) the next-of-kin may live far away. Will the party send a message by courier and hope for a response, or make the journey with their grim cargo?
Laying victims to rest encourages a thoughtful, respectful examination of NPCs who are usually easy to disregard. As part of the investigation, the party will learn a lot about the setting and meet many characters, and probably generate more goals and quests.
Do I think the players of Critical Role should have taken this approach instead of what they did? No, their actions made sense for their characters and the campaign they are in. This idea doesn’t fit Critical Role. It doesn’t even fit Dungeons and Dragons, since relationships and investigation are so important, and D&D doesn’t have much to say about those things. But I’m sure there exist a GM, a party, and a game system for which this would be amazing!