Didn't bother to read the whole thread, but I've got an answer to bastillebaston's problem.
You say that axe rush is overpowered. If you don't get axes, you use catapult rush, which you say is overpowered. Then you say that grenadier rush is overpowered.
See any link between these?
Of course you can conquer other nations if you have way more troops than they! It's simple mathematics, 2 attacking grenadiers are better than 1 defending grenadier. 2 attacking axemen are better than 1 defending axeman/spearman/archer/whatever. If you have something technologically equal but way more of it, your chances to win are way much better.
Exactly. And as far as balance goes I think it's about right. Sure it would be fun to have long drawn out sieges where you have to pillage the surrounding country side and slowly wear down the opponent but in realistic terms each game turn is a long time and you could be trying to conquer a city for 60 years!
It's a tough thing to get the balance between realism and game balance. But for me there are a few things that I would like to see changed to make the earlier game period tougher (and in general).
1) Fog of War and map making. It's entirely unrealistic that Warriors/Scouts can travel half way across the world and the civilisation automatically remember every hill, plain, resource etc. I'd like it that the fog of war is only lifted for a turn or two outside the cultural borders. Then when something like Copper appears you wouldn't automatically know where it was.
2) Warriors should only be able to travel so far from your nearest City, a bit like the way planes can only bomb within a certain area. Why? Because it's unrealistic that an army can travel halfway across a continent not requiring food, resource etc. Or to limit SOD's they could apply a health penalty for every unit outside of your cultural border. So the more units you have outside of your cultural border, the less powerful they are due to starvation, disease etc Later techs and buildings could increase this range etc, and forts could act as "safe havens" and be allowed to be built in enemy land (as long as there was a trade route to stone etc). Scouts/Explorers could be immune from this penalty, making them more useful in war time situations as well as peace time. Maybe Scouts/Explorers should automatically start with a strong withdrawal chance also?
3) The fog of war should remain like that until the civilisation is advanced enough to make maps. Perhaps as the cultural influence of a city increases then line of sight outside of its borders also increases. It could be that Explorers have the added benefit of everything they see clears the fog of war for good. This makes them much more useful later game than they currently are.
4) I personally think the production of military units could do with being tweaked. I think Copper and Iron shouldn't enable you to make Axemen, Swordsman etc but give them a massive production boost to building them instead. Same with Horses. I think that all civilisations should have access to Copper and Iron as a default, but that they need a resource tile to speed up or mass produce units requiring it. I think food should also be a massive factor in how fast a city can build human based military units. Planes, Tanks etc would still rely on your civ controlling an Iron resource though. I do not think, with the exception of wooden based ships, that units or settlers should be able to be chop rushed. Cutting down forests does not make babies
5) Perhaps all cities should be able to make Warriors (militia), but only those with a Barracks can make more advanced (eg Axeman, Spearman) units. Or perhaps the Forge should be able to be built earlier and a City can only produce Swordsman if it has a forge.
There are many ways for the game to be changed, but whether or not they'd improve the game is another matter. I know this post has gone off topic so I will also post most of it in the suggestions forum.