They've improved the combat side immensely, but they've reduced the empire management side so much that it's not really Civ anymore. It's more of an Age of Empires type game now rather than Civ which has always been about balancing military, economy, science, population etc. It's nice to start because it's so pretty and combat is improved with but it doesn't take long to lament the loss of all the depth in empire management.
Basically they've dumbed it down.