I actually have made a modification for Warband where I've added random events. The type of situations I add are ones that come with good and bad consequences depending on what the player chooses. Normally a person goes about what is the right choice. But if someone can make a choice and deal with what consequences they come with regardless if it is bad intentions for a good outcome and vice versa. These random events help to mix up gameplay and challenge the player without hurting his gameplay experience and furthering immersion.
Those types of events are much better than your usual disaster scenario from Sim City or GalCiv2; and more like deciding if that mega prison or epic mall will be a good benefit or eventually bad thing to build in your "Sim" city.