Originally Posted by GothicGothicness
I guess they added that to make some changes at least, otherwise they could just say look it is the same game but with updated graphics.

And since that was the knock on Civ3 (graphic update of Civ2), they really had no choice but to mess with the fundamentals a bit. Adding religion and culture did make the game more like a real world sim, which might have been the top-level goal.