I'm so unhappy with CIV5 that I created an account just to tell you.
I have played Civ 3 and 4 and Revolutions so I'm not new to the game. I have loved each of the previous games and didn't even think about whether I should buy Civ5 based on the strength of those previous games. However now I am so disappointed that I will be thoroughly reviewing all the features of Civ6 and playing through on someone elses computer before I commit to buying it.
Why am I so unhappy?
You have turned the game structure into a frozen talent tree. Civ's cannot change once their policies are in place. As if Civilizations have never changed their stance? Japan used to be a warrior country and in some ways they still are, but now they do battle in economics, not with swords. A game doesn't have to be realistic to be fun, but it does need to be believable.
WHAT?!! No religions?! For this reason alone the project manager should be fired, instantly. Religion is a fundamental aspect of a civilization and to remove it from the game is a waste and a shame. You can try to claim that religion isn't important in society and civilization, but you would be wrong and I won't waste my breath explaining why.
They are meaningless in this game. Why bother even trying to get something within range? Just go for population and money and win. I understand trying to make Civ more accesable to people. But by dumbing down the game as far as you have, you have alienated the very people that made this franchise a success.
Essentially I feel that a new game should be everything the previous game was and more. Not less. If you hadn't played previous Civ's you probably won't miss or understand the importance of these components. But as far as I'm concerned I have been let down and unless Religions are part of Civ6 I won't be wasting my time buying it or any expansions for Civ5 for that matter.