TSA writes: Sometimes it feels like its better to tear everything down and start again, and its tempting to think thats how big video game sequels work as well, but its never truly the case. Developers will always learn from what they did before, whether its a narrative adventure or a large open-ended strategy like Civilization or Crusader Kings. Sequels can sometimes be less about rebuilding from scratch and more about refurbishing previous ideas.
Source: N4G PC Crusader Kings III a new era of intrigue, religious wars and grand strategy (TheSixthAxis)