It's not powercreep, it's just not good value and comes later compared to CQC options of similar strength of other factions.
PPsh conscripts dominated the meta after they where patched, that mean they have been power creeped. SVT currently is far superior the PPsh for instance.
An M3 at this timing would be useless. You can upgrade the M5 with the Quad so it can grind stuff at long range, you don't want to be doing drive-bys at 3 CP (the 7 to 8 minute mark).
Maybe if you reduced it to 2 CP and replaced the M5 with USF Mechanized's Assault M3, I don't see a need for it though.
That is the m3 I was talking about the one that can drop medic kits or it could even be a difrent type of M3A3 with different abilities.
While I agree IL-2 bombing strike should be replaced as well, vehicle detection is the most useless ability I can think of in the Soviet ability roster. If Vehicle Detection is kept, it should be an ability available to every infantry squad individually and only cost 15 munitions to activate like on PTRS Conscripts and AT-Rifle Sections (cost should be lowered on Schreck Storms as well).
All faction need weak abilities do combine with strong abilities and keep the average power of commander at about the same level.
Your suggestion about VD could work and I had suggested a similar thing.
Anyway, a supply truck really wouldn't be that strong outside of 1v1, because resources aren't shared. An exception maybe maps with a very safe fuel, which aren't common.
Allowing extra fuel for a commander with ISU/Elefant/JT is not a very good idea.
B-4 is AT themed, or it wouldn't do 640 damage (or 480 + stun as I suggested). I can find you plenty of compilations of B-4's killing vehicles.
If B-4 was only AT I would say yes. It also AI and anti structure so I say no. That is also way the AT bombing needs some tweaks.
Tank hunter commander is currently one of the most efficient commander in taking out OKW truck and B4 would only make it more efficient.
This sounds contradictory: reducing the number of common abilities, while increasing the number of rare abilities. You'd have to design a lot of new abilities if you want to accomplish that.
I tried to keep it reasonably simple with 1 ability swap max and creating new abilities only if the assets already exist (ZiS supply truck and smoke drop would be reasonably easy to add).
A unit as powerful as Shock troops could be the selling point of a commander but why get a commander that only has Shock troops when you can a commander with shock troops and IS-2/KV-2/ISU-152?
Those supper heavies (for all factions) should be combined with weaker abilities so that the total power of commander be balanced out.