Suppression from 0.00005 to 0.00006
Suppression versus suppressed targets from 0.5 to 0.65
Suppression versus light cover from 0.5 to 0.75
Suppression versus heavy cover from 0.1 to 0.2
Nearby suppression modifier from 0.8 to 1.25
What is going on here? Surely you don't have to change the values vs cover & suppressed squads that all other machine guns use to get the maxim working correctly?
Given OKW design, we had to give Maxim long burst to allow OKW infantry to jump back and avoid being locked down by the Maxim.
However, due to the fact that it takes so long to deliver the burst, we found out that the Maxim was hot trash vs blobs (put 5 Volks on top of one another, and right click behind the Maxim; only one will end up being suppressed). This is because you can't afford to change targets easily with the Maxim to suppress (else you cancel out your burst). That explains the suppression vs suppressed modifier, and the AoE suppression modifiers.
The reason why we messed with cover modifiers is because the Maxim deals low base-line suppression (again, to avoid 1-v-1 maxim spam). However giving the Maxim the normal cover modifiers with lower suppression means it wouldn't function in the late-game. Think of it what happens to Vickers MG in the late-game (with cover craters everywhere), and multiply it by the fact that Soviets don't have Tommies; they have Conscripts instead.
Going the third route, which means simply increasing Maxim veterancy to offset terraforming means that if, at any point, your Maxim gets wiped, you no longer have access to reliable suppression when you most need it (i.e., when STG Volks are raping the conscripts). Allowing the Maxim to work OK in the late-game off the bat will ensure that T2 has some merit as a tech tier in the late-game.
PS: If we ever want to make Vickers worthwhile for the late-game we would have to apply similar anti-cover modifiers (if its range goes down, that is).