All the most important boxes are ticked - The REF buildup is not so severe, at least for the lower difficulty levels - The AI is improved with the Natives more aggressive and the Europeans much stronger, and you also cannot attack them in the first 20 turns - Education is heaps better and you can now train veterans - guns and horses are more expensive so you need to manage your own production - colonists can now move to, and join a colony on the same turn - You can leave your independence declaration late and still have 100 turns to win - no CD required to play etc etc
I enjoyed the game when it first came out, but these changes make it even better.