The difference between musket corps and infantry corps would be one unit upgrade while the difference between musket and rifle corps would be two unit upgrades assuming that corps could be seen as a unit upgrade.
Corps can't be seen as a unit upgrade as they (allegedly) increase the base strength of the unit by 40%. So the only way a Musket corps and infantry corps can concievably be considered 1 unit apart is if the infantry is close in strengh to the musket.
Otherwise it would go musket-> M corps -> Infantry -> Infantry corps
Which runs into the problem I mentioned, no one is going to build infantry if they can build infantry corps. So it still creates the problem of me getting to Infantry before you creating a huge gap if both of us have access to corps.
I assume that they balance the game around that you are in the same era with culture and science.
This is just virtually impossible unless the players were actually restricted from specializing in one over the other, which we know we can do. If I never build a campus but spam theater districts everywhere then I'll progress through the civic tree quicker than the tech tree - the reverse also being true.
By the end of Marbozir's playthrough he's generating 50 science and 30 culture. he still has medieval civics left to learn while he begins his first renaissance civic. Conversely,
all of his medival techs are finished, about half of the renaissance ones are done, and he's learning his first
industrialtech. So he's more advanced in tech than he his in civics. By practically an entire era.
Of course players who keep a balance can certainly progress similarly but to suggest I can't zoom through the tech tree at a significantly faster rate than culture if I'm so inclined, pretty much removes the point of splitting up the trees and allowing for city specializations in the first place.
Population seems to generate half the culture as it does science. So if you're building campuses and no sources of culture then there's no way you would keep to your techs with your civics unless the game prohibits tech/civic expansion by tying it to the other. If it's balanced in such a way that you
would keep up under that model, then doing the reverse - spamming culture with no science, would now be off balance.
There are a lot of variables to this game - if you're spending good spots, time, and resources on generating faith because you want to play the faith game, and I'm just focusing science, while your science is modest, and both of our culture is modest - I'm going to have more advanced units than you by the time we both get corps.
There's no way around that without putting in barriers. If a player is going to progress through both trees evenly then they're going to have plan it that way.
