This game is intended to be similar to a Roguelike in the end, in that permadeath/only one save/forced save on exit will be the typical intended game experience. However, just because that should be enabled by default doesn't mean that the game shouldn't provide for the option of disabling that in a game. While I am inclined to agree that save scumming in a game like this will deprive you of part of what makes the experience entertaining.
http://www.escapistmagazine.com/article ... ve-Scummer
That doesn't mean that there aren't people out there who will do whatever they have to to play the game they want to play it, including killing the process or what have you. It seems reasonable to simply leave that possibility in, and perhaps reward people who are willing to take the risk of Hardcore mode in some way. Perhaps faster Althetic/Strength stat increases, to make up for lost units, or something akin to that.
As for the body decay, I would love to see the bodies get picked over by NPCs, perhaps even get gathered up by NPCs accounting for what happens to the corpses. It's more than a little disconcerting to see a corpse disappear right next to you, so perhaps one option is to simply disable the "decay" functionality for corpses within a certain distance of the camera. In the end however, I'd really like to see there be something useful to be done with corpses. For example, from what I understand once some of the more caustic fluids are removed, bodies can make useful fertilizer. How cool would it be to have a sort of corpse processing area, where you compost bodies and make fertile soil? The cannibal race could cut to the chase and process bodies for more, erm, immediate consumption. Perhaps the cannibal race could utilize other bits of the bodies as well, working human bones into their armors to be more imposing, that sort of thing.
To me it seems that corpses would not go to waste in a desolate land, especially not if they could be put to better use. Even if some of the factions held the use of human remains as taboo and wouldn't make use of them in any way, that would add another aspect to the game. Perhaps a few factions would dislike any use of human remains other than burial, many factions would frown upon staking your enemies out to die of exposure as a warning to others, most people in the world would cease friendly relations if they suspected you of cannibalism.
Those possibilities would likely require very little in the way of new AI interaction routines, the animations for picking up bodies are already present, and it would not only solve the whole "body decay" issue but make the world feel more alive, and present you with more options without some simple binary right/wrong as is too often the case in games today. The decisions on how you would deal with human remains would give your faction diversity that would even allow for replayability. Do you bury your dead this game, use them for compost? Or do you eat them, decorate your armor with the bones of your foes, and place their heads on spears outside your settlements?