Wonders are pure game elements that have no basis in reality, unless you simply justify that pride in your wonder motivates your people to do wonderful things.
I think most wonders did have effects similar to that, but usually in ways DIFFERENT from how it's represented in the game. For example, the Pyramids: during the *construction* of the Pyramids, it dramatically increased the happy cap for Egypt because they were occupied with the building effort. After construction there was a sort of "amazement" effect that resonated internally as greater religious devotion (perhaps a shorter whip-anger IF the civ is in Theocracy, or maybe just a generic +1 happy), and a +1 diplo modifier from other kingdoms that tended to suspect that whatever black magic Egypt had that enabled the construction, might be applicable to the battlefield, and they'd better think twice before trying to invade that land. The pyramids did not, in fact, enable modern-era civics, nor did ancient Egypt ever attempt a switch to such civics.
One of the most ridiculous wonder effects is Statue of Liberty. What could possibly be the connection between the completion of that statue, and every American city having a free specialist in real life? The real effect was that New York City was essentially able to double its cultural influence.
In fact most "wonders" IRL are cultural in effect; nothing more, nothing less. Civs tend to build them when they want to boost their cultural influence.
Some other wonders just need minor tweaks. The Pentagon doesn't necessarily give American soldiers free XPs when "built" at basic training camps. What it does is allow more effective command and control of the troops during force projection, and create more jobs for military bureaucrats that aren't exceptionally good at anything but shuffling paper. The effect there would be -50% military unit maintenance cost, and +50% commerce yield of the city where it's built (boondoggle jobs).
But slavishly following detailed realism gets into a morass. Elegance, bang for buck, is the ideal here.
I can agree to that, although I have a theory in slight counterpoint: in those areas where the game gets incredibly imbalanced, the answer to bringing the balance back *IS* in fact, more realism in those areas. How do you prevent 200+ ridiculous stacks of doom brute forcing their way to conquest? Well, how did real life prevent that from happening? Oh, you mean you have to FEED the troops too? Keep supply lines open? Keep the troops happy and healthy just like cities? D'oh.........
I think the Monty issue is best dealt with by simply getting rid of the money bonus from capturing cities. This is what makes warmongers economically viable is it not?
The money bonus is realistic, but with Monty the more unrealistic aspect is that he's able to field an army about 500x his citizen population in order to take said city. That's an example of where realism should be called upon to bring balance back to the game.