Given the massive number of bodies that can pile up in the late game. I think adding a method of turning bodies into food. Either directly by turning it into nutrient paste (corpse starch, solyent green, etc.) or using it as fertilizer. Its basic recycling to make use of it and you only have so much room to bury people. While I think the idea of recycling the dead would be pretty common in the future. You could attach a moral penalty to it, which would be greater if you used your own people.