Although something I would like to see is NPCs getting suspicious if you wear clothing/armour that you have taken from someone you murdered. For example if you wear a guards armour in town other guards may question who you are and why you're not on duty. If your speechcraft or related skill isn't high enough to convince them of a plausible excuse then they could raise the alarm.
Similarly if you wear a magic ring/clothing/armour or weapon that you took from someone you killed then go to the characters home town other NPCs should ask about it.
"Hey, I recognise that shield. That belongs to ..... They've been missing for days. How did you get it? STOP, GUARDS - THIEF!"