I tempted to leave this page blank, but here goes:
- I love that cities can now be random shaped, and that you can push boarders out further. Makes it easier to site cities, removes the need to build "fill-in" cities to work left-over tiles, overcomes the frustration when you discover a latter resource just outside your city, and greatly lessens the temptation to burn captured cities because the AI built in the wrong spot.
- I love the use of Ranged Units.
- I like that Culture is now good for more than just pushing your boarders, and that Civics now have their own tree. (I think the system could work better, and be more transparent, but its a good innovation.)
- I like the different policies, so that two civs can have the same form of government, but completely different policies.
- I like that you can establish your own Religion, rather than getting it based on techs. I also like that each Religion will have different beliefs, rather than the same effects. And I like that Religion now has its own points system. (That said, I think the overall Religion system still requires massive work.)