this is not a simulation
this is a GAME
in games sometimes realism has to be sacrified to gameplay
This is an interesting (and probably common) retort to some of my criticisms, so I want to respond.
ddd123 is right that many of my complaints about Civ V include the fact that the rules do not "make sense" or correlate to anything real about history, civilization development or reality in general. He's probably not alone in feeling that this is a dumb criticism because "this is a game" and so who cares if the rules make sense.
I generally agree that it's a game, not a simulation, and so some rules are going to be mechanical necessities that don't really fit as models of reality. For example, the incongruity of strategic and tactical time in Civ. On a reality level it doesn't make sense that in each turn my units only move a few spaces on the map - the turn is 20 years! But this is a function of Civ's game design, which merges the strategic and tactical maps, a design that has a lot of advantages in simplicity and gameplay etc. I can accept that completely.
But at the same time, I think ddd123 is making a fundamental mistake about what makes a game "fun," not just for simulation lovers but for all game players. I am confident that even people like ddd123 derive a huge percentage of the fun from any game they like from its story, ambiance, etc. It is not "just" a game wherein the fun depends only on the rules and how they are balanced. That's not how games succeed at being fun, and this is universally true, including for people like ddd123.
I can prove that this stuff matters to everyone by pointing out that we could in theory strip away all reality from Civilization without changing any of the rules. The map could be just a piece of graph paper; the turns would just have turn numbers and not years. You could call a "City" a "Node", a Granary "Food Building One", etc. And so on.
But this would be incredibly unfun, and why is that? I think we all understand it intuitively. The rules of any game have to correlate to reality in some way for it to be fun. This is even true for simple board games like Monopoly. There is almost no game in the world (maybe checkers?), and certainly no complex strategic game, that is all rules and no "simulation", and that's for good reason. We are not computers and it's not fun to make our choices in games based solely on an analysis of maximizing our chances under the rules. It is fun to take cues from our intuitions about reality to make game decisions - i.e. in CIV we safely expect a tank to be a stronger military unit than a spearman. Not only is it fun for games to work this way, but the rules of complex strategy games would be much harder to learn if they didn't correlate to anything real.
In Civ 5, much too much of my time is spent maximizing my chances under rules that correlate to nothing. Yeah, I can learn that if I pay 500g to Maritime City X, all my cities get a lot of food. Oh look, my "happiness" is negative, time to build Happiness Building One. The forumlas beneath these game mechanisms are transparently obvious because they have no other meaning.
So yeah it's a game, but games are fun because of the overlay of rules onto a coherent system, a metaphor of sorts for something real. It is not sufficient to say "it's just a game" about every game mechanic that is completely unmoored from reality. And in Civ 5 almost every significant rule suffers from this problem.