I did not read half of the posts since I have been reading the same kind of replies for weeks now. I just want to say this: this is not civ IV, this is civ V. Try not to change the game but yourself.
I hear you, but if you
did read these posts, you might find that they're not all complaining about Civ5 being different than Civ4.
Believe me, two short weeks ago I was in the same position you are now, telling myself that all the haters were just afraid of change or whatever. (To be fair, the shrillest complaints are usually the most apparent, and they really overwhelmed the reasonable but disappointed people who had valid points.)
I don't want Civ5 to become Civ4. I actually like a lot of the changes introduced in Civ5. I enjoy 1UPT, city-states, social policies (though I think they could be tweaked) and the revamped UI. But once my excitement about those new features faded and I dug in to game after game, I got stuck with a lot of "Next Turn, Next Turn, Next Turn" boredom.
The root of my problem is the AI, especially in regards to combat and tactics. It just doesn't challenge the player much at all. Any game that I can win whenever I decide to win it becomes pointless to continue. And yes, harder difficulties will make that victory more difficult to attain, but they don't make the AI more challenging - they just give you more penalties to overcome, and give the other civs more bonuses. (Wonders completed on the 10th turn of the game, for example.)
That's just my experience. I hope it's not yours. I don't want to be "right" here; honestly wouldn't want any other longtime Civ fan to feel the peculiar mix of sadness and loss that I'm experiencing. But my response to the game has absolutely nothing to do with the fact that it's not Civ4; I've been evaluating it on its own since Day 1. I just can't avoid feeling bored and let down, as much as I'd love to be cheerleading for Firaxis right now.