My own relationship with Galactic Civilizations III is complicated.
At most studios, when a game changes designers, it is because the previous designer had left. Soren did Civilization IV and then left (and eventually came to Stardock and now runs Mohawk). Jon Shafer designed Civilization V and then left (and came to Stardock and then later formed Conifer Games).
But while I designed GalCiv I and GalCiv II I went on to design Ashes of the Singularity while my friend Paul designed GalCiv III.
It’s not easy to design a game while the engine is being built. Remember Elemental? That started out as a Master of Magic style game that slowly morphed based on what the engine could and couldn’t do.
Engine aside, GalCiv III at launch is a somewhat different game than I would have made and that’s pretty tough when you’re still working at the same company.
Now, Crusade is mine. And the difference between Crusade and the base game is substantially larger than the difference between GalCiv I and GalCiv II. It’s not GalCiv III + new features. It is a to bottom re-design of the balance and pacing and user experience.
Here’s GalCiv III:
http://media.gamerevolution.com/images/games/pc/galactic-civilizations-iii-mercenaries/galactic-civilizations-iii-mercenaries_016.jpg
Look closely at the UI, the shape of the influence, the lighting, what information is available.
By contrast, here is GalCiv III: Crusade
You can tell a lot about a game’s focus based on what data it chooses to present. For me, civilization games are mostly about the economics and culture you build. Other people tend to prefer war and combat.
You can kind of see that in Civilization IV vs. Civilization V at launch. IV was much more about economics and culture while V was more focused on war and conquest.
Similarly, while Crusade implies war, it is, as the UI makes pretty clear, much more about your economy. War is there as an alternative means of obtaining the resources you need.