I have some ideas based on something that happened to me in Adventure Mode, but first I must explain the story before the ideas.
I once showed up in a town hall where nobody would talk to me. I had no idea why, as I had just discovered that town and had not had any time to do anything to them. However, every single person in the town instantly became hostile to me. Suddenly, the mayor, and every guard, drunk, peasant, and child began to come out of their houses, en masse, swinging and flailing at me. (And most of them were cloven asunder by my counter-attacks.) In order to halt their advance, I thought of an interesting idea, and began lighting trees and dry grasses on fire like pyro, creating a wall of smoke and flame, which, soon enough, prevented their advance signifigantly. Now, I lit so many fires that it was practically all smoke for hours. Except it didn't seem the fires were spreading. So eventually I went back from the outskirts into the town to wander around. I knew all of the merchants had been killed, and were I a proper murdering barbarian I would be able to loot. Sadly, this is not the case, because even with the shopkeepers all dead (5 of them) all of the goods were still someone else's property. Eventually, I left.
1. Make towns/civs more reasonable on their dislike of you. It seems like everyone in a town/civ instantly knows if you tried to shoplift a fish, and may even all decide to attack you en-massed in a hopeless battle against a godlike swordsman who's face is on the crafts in that village.
2. Make children more skittish than adults. Seriously, why am I getting mobbed by fearless, unarmed berserker children who I have to decapitate with counter-attacks, since when are kids /that/ bad?
3. Make fires spread into buildings/across grass/into areas with the right conditions. I actually don't know, do they do this already? It certainly didn't seem so with my experience.
4. Make NPC's know when they've lost. If I'm standing in a pile of dozens of warrior's weapons and corpses smeared with blood and a maniacal look in my eye, Epo Turtlewalk the peasant shouldn't decided to charge me and punch me.
5. Make NPC Goods theft-able. Whether by pickpocketing skill, stealing, or just letting us take the stuff that belonged to a dead shop-keeper who died in a fire. That Iron Masterwork Greatsword isn't mine, really? Because I could have sworn I killed everyone in the town. I didn't know I was that moral.