You can probably also go Pioneer-spam blobs. I am pretty sure you will be able to win the first few engagements, but you will start losing 3 minutes into the game.
Yes, you are probably going to see a ton of Penal-only blobs when the patch goes live. However if we've done our job correctly, Penal-only blobs will be unviable (or at least less viable than Penal & Guards blobs). Thus, you are not going to see much of them after the novelty factor wears off.
There is nothing else to build on Soviet T1, what do you expect from players? If they are smart enough, their not going to blob, simply spam and flank.
The way you focus on Penal scare me a lot. You (and me) have no idea how people will use it, what kind of silly OP strat someone will find from what you change and ruin your patch.
But I can already tell you with the change you do on Penal, T1 Penal spam + lend lease commander will be more than broken. I know cuz I did it.
You are simply putting too much changes on this one where a couple of located nerf/up would have been sufficient for the sake of the balance. You don't know how people will react, you need more data than 10/20 replays per patch version.
My advise: Let the penal be strong AI as before, only remove FT upgrade and tune its Vet3, nerf Guards AI like you did, make it more vulnerable vs infantry, and stop. watch the trend for a month to see how players are managing this.
Do the same for the t-70 and Stuart/AEC but don't nerf others LVs and LTs, brings some up to the okw flaktrack and 251 and done.
Tune the USF mortar, the rifle vet3, keep the nerf on RM+1919.
Maybe I forget some other minor changes, but the most important is:
make it live for a month and watch the trends.