In my current game, Asari are one city away from conquering the Khuzaits.
The game is balanced to the point that this snowball of resources doesn't occur for a long time, and is different every time. I think because the balance is actually pretty good now, everyone is going to have a different perspective because random chance is playing a greater role.
The variable is the human. Because everyone plays slightly differently, and the systems are interconnected - the consequences of player action are going to be different every time for every player. Systems are interlinked - butterflies in Africa occurs... a human buys food in Onira, it changes the price of food which changes the economy in a region which changes the outcome of a war etc (exaggerated for effect). But the more a human forces themselves on the game, the more the downstream of their interactions affects the world and the more likely a snowball is to occur.
Long winded way of saying that balance is pretty good now.
Got nothing to do with cavalry. It's almost entirely the geography, and the situations of the initial war. Khuzait has the least access points into their realms, and right after the initial war everyone is engaged in with some other nation, the odds of Khuzaits entering a multi-front war against 2~3 enemies at the same time, are simply the lowest of all the countries.
Sturgia, otoh, has two large access points west and east. The eastern point is very narrow, and pits them against Khuzait cavalry, which, as a predominantly infantry nation, are disadvantaged from the start. On the western front it has a broad access point that borders 2~3 nations at the same time, and when one town closest to the frontlines is lost, they are bottlenecked and isolated, without being able to counter-attack effectively,
All the rest of the nations are in a toss-up and any nation that gets gangbanged will quickly deteriorate.
That's why in the long-run, the most common situation you see is that of (1) Khuzaits becoming super powerful, (2) Sturgia usually eliminated, (3) everyone else in the middle all deteriorate or get one prominent nation.
Khuzaits have a ton of entry points and even a relatively large border length especially when considering access to Sturgia which is one of the reasons the Khuzaits always seemed to devour Sturgia . The Khuzaits also always capture Amprela (or whatever it is called) because it is directly across from a main access point.
As far as a multiple front battle, You have Sturgia, Northern Empire, Southern Empire and Aserai all bordering them. Aserai to be honest probably has the least access points. The ones who have it the worst though are probably the Battanians. They have 4 empires with almost 100% access to their lands, Sturgia from the north, Northern and Western Empires from the East and Vlandinan from the West.
Totally agree speed played a big part on Khuzait dominance. Fighting against them we could see allied smaller parties getting picked apart by 3-4 others, while their armies could almost always evade combat when in a disadvantage. After some time, attrition and the hit n' run warfare always paid off.
I started a new campaign after last patch and Sturgia finally got their snow speed bonus after snow speed penalty was implemented and they managed to conquer that whole region between them, the Battanians and the North Empire before 100 days, extending all the way to Car Banseth. We might just change one superpower for another. Let's see how others' campaigns have been playing out
Yeah I do honestly feel this way. This is one of the reasons that Mod that slows down armies outside of friendly terrain works to curtail snowballing effects. It makes it so invading armies can always be caught by the defenders no matter which faction is invading.