I'm happy that you put in the effort and instead of just posting a faction rework idea you made it into a mod. Good job!
However, I have to ask - what's the idea behind requiring both Soviet T1 and T2 to build T3? It's kind of funny how Soviet changes fit in just 3 lines, while other factions require several.
These changes are designed to give all factions access to AT guns, MGs and mortars, no matter which tech path they take, as long with a few balance changes.
The sov changes are so short because all I wanted to do was allow T1 to still have Mgs and AT guns .
I did this by reducing the cost of T3 but requiring both T1 and T2 to be purchased to construct T3 which essentially makes it "free" but mandatory to back tech, which was simple to do.
Balance changes:
I also think sov is struggling right now, but mainly against osttruppen builds, so I nerfed osttruppen (wich I've now realized I forgot to mention)
For OKW, I wanted them to get Indirect fire faster, So I reduced the cost of Battlegroup. I also always wanted them to have medics, so I made their tech linear (so they always have battlegroup), and reduced the cost of each building slightly so the overall tech cost was the same as before.
I also wanted to preserve the choice between Luchs and Flak HT, so I added side techs like AEC/Bofors for each.
Balance changes:
The first truck arriving sooner meant that Stg 44s came too early, so I changed their tech requirements.
Finally, OKW infantry currently struggles late game, so I made obers come a bit sooner.
For USF, I wanted to do the same as I did with Sov, making back teching for team weapons mandatory but decreasing the cost of T3 to compensate.
However, the fact that you need to get an officer to unlock your team weapons meant that the player might end up with too much infantry if they were forced to back tech before getting major, so I split the officer from the team weapon unlock.
Balance changes:
I also added my Pack howitzer and M8 scott rework ideas, as they are both considered problem units.
Ostheer
Balance changes:
I think grenadiers are not suited to their role of defending the Mg42, so I gave them stun grenades so they could stun enemy squads and give their mg a bit more time to reposition
Panzergrenadiers were moved to the T1 (Infantry company) to reduce the power of the osttruppen T1 skip build by requiring them to invest more mp and fuel to get panzergrenadiers
StuGs were changed to make them better vs high HP targets because ostheer currently lacks a tank with good dps
Also notice no Brit or Ost tech changes because they already get access to MGs and AT guns
So, o nswer your question, Sov changes are short because their balance problems mostly originate in a different faction having an OP strat, and the changes needed to always give them team weapons without changing their overall tech cost was very simple