User blog comment:LostInRiverview/The Sims Wiki News - 31st October 2013/@comment-1727959-20131031151851/@comment-1519608-20131031164326

They probably wanted more realism, and for there to be an incentive to build an efficient city (so emergency services can travel around easily in the event of a disaster). FWIW SimCity 4 had no "random" disasters except fires and riots (which could be prevented completely if the map is adequately covered by fire and police stations).