I was at first a little disappointed with 5, any time you play a game you love for so long the change in mechanics can be disturbing. But even though I was somewhat disappointed I still had to play a few more turns and ultimately that is what makes this series what it is.
Does the game have warts, absolutely, how it got through play testing with the AI,diplomacy and graphic issues is beyond me but I have no doubt that the core of the game is excellent. 4 had issues when it first shipped as well, I am fairly confident that the mod community and Firaxis will eventually get most of the issues resolved and four years from today we will be saying this is a great game, way better than Civ 4