A rough rundown of the Revenge system, otherwise known as the Enemy preparedness system. Currently just pasted from a number of forum posts.
There's a bunch of missions where it's not enabled at all, or rather forced to a certain config for that mission And a few where just stealth vs combat revenge configs aren't.
The max revenge level increases as you complete certain story missions. Hard missions are max revenge/ignore blocked.
On top of this levels are limited per type, the rest are anywhere from 1 to 7, with an average of 3.
Each level has a current value, and the level raises per 100 points.
Revenge values except stealth and combat type are reduced on successful mission completion. Not free roam missions. If you use chicken hat all values are reduced on every mission exit, even fail.
The maximum reduction is 50, ie half a level, or 100, a whole level for chicken hat.
The rest have to be specifically blocked by sending off dispatch teams. Successful dispatches will block that type for 3 missions, whether successful or aborted.
The total revenge level also ties into the staff morale somehow. My rough read on it is the higher the revenge levels against you the better staff morale (ie i cant make sense of it being the reverse), as to how much of an impact it has there's too much to it for me to decipher for now.
The reason stealth and combat values are handled differently is they run a 'tendency' system for the revenge config.
There's a bunch of 'triggers'/actions to cause a direct revenge value increase for a type, headshots, eliminated by stealth, or combat (basically alert level), 'annihilated' for the same. killed by heli or vehicle, waking up comrades, being smoked, seeing smoke. They increase the value for a type by 5-15
All this drives the 'revenge config' for the soldiers when a cp is spawned, it adds a bit of randomization and a chance of types by percentage (which increases by revenge level for the type) for stuff like armor, helmet. And what seems to be straight up numbers for different types of weapons. how much reinforcements are available and how heavy they are.
There's maybe a bug in the fulton config, there's fulton0 = fulton low, fulton1 = nothing, fulton2 = fulton high, fulton3 = fulton special. I assume it's supposed to be fulton 0 nothing, 1 low, because the function that reads the config doesn't seems to only get one config/couldn't pull the value of other if blank.
Incidentally I also don't actually know what soldiers with those types actually do in the game. I've seen them shoot down stuff but that's about it.
The values you directly drive for combat and stealth via eliminations/kills only select the 'tendency' in a table, these are reset each mission.
The tendency table drives a shift between the secondary combat/stealth values (ie 'stealth' tendency (at max) gives stealth +50, combat -50)
The values shift between stealth and combat, you can increase by up to half a level per mission, but at high levels the opposite type will be decreased by the same amount. if you don't eliminate or kill anyone (or kill and eliminate equally) they you'll pull the 'DRAW' tendency Which at low level will add to the value and high level reduce to both types (still depending on the levels of the types.)
This means if you ghost levels will rise/lower, to an equilibrium of level 4 for both, I'm not sure how the tie break is decided. But at a max shift of 25 a mission, 100 points to a level and up to 3 levels this will take a while.
Anyway, after all that talk the actual configs resulting from stealth are things like cameras, decoys, mines and the ability to knife counter to holdups, combat is 'soft armor' which I'm guessing is body armor, shotguns, shields, reinforcements.
Each 'mission' sets up the enemies with the loadouts guided by the revenge config. So loadouts wont be seen to change till next mission (including Dispatch mission results).
'Free mode' is it's own mission, I don't think side missions are (though there may be some special ones that break into a 'full mission'?). Starting main mission from free mode is loading new mission, and I assume going back free mode from mission. I really need to check this stuff directly again to get the exact setup.
Free missions don't modify the combat/stealth tenancy/levels
The whole tendency system is balanced to try and reach an equilibrium for the overarching stealth vs combat categories (not to be confused with the individual stealth or combat revenge level) provided the player doesn't provide any 'input' to those categories. So unless you have a very specific goal this too should be left default.
Changes to REVENGE_POINT_TABLE will change the rate at which you shift through the revenge levels.
The revengeDefine categories aren't cumulative, they're whole configuration selected by <CATEGORY>_<CATEGORYLEVEL>
Also the revenge config selection does not combine stealth and combat categories in one mission, it's one or the other, either overridden by the mission setting, or selected by your overarching combat vs stealth revenge level.
If you are doing total ghost, ie not interacting with enemies at all, then you're not actually increasing the system anyway and it will actually slowly decrease (the rate of that is actually something that might want to be analyzed).