Infantry's overvalued in combat due to the way combat ranges work. You have one round at long range, one at medium, and two at short range.
If you look at the detailed combat reports, you will see that infantry squads inflict far more kills than they ever did historically. Artillery, which was the big killer in WW2 at about 70% of KIAs/WIAs, doesn't come anywhere need that level in the game.
And when the Russian squads upgrade to the SMG TOE, German losses then go through the roof if not in fortifications.
There are a lot of factors that play into the CV loss calculation - TOE, weapons, leader's die roll, supply, morale, experience, terrain, fortification level, odds, etc...
But if you have two units, same morale, same experience, same supply level, same size and one of them has 50% more infantry squads, it will win about 70-80% of the time based on test that I have run. It doesn't matter if its motorized vs infantry, etc... It's just the way the combat system is designed. And the Soviet's infantry TOE are heavy up on infantry squads and get heavier as the was goes toward 45. And thier squad's firepower keeps going up.
This is an observation on the combat system, neither agreeing with the approach or disagreeing as I both like it in some ways and dislike it in some ways.
Artillery doesn't seem to inflict many kills based on the test I have run (exception: ATG vs tank units). What they seem to do is inflict some type of command & control losses/disruption on the targeted unit. And it seems to be an all or nothing type gig from what I can see. Either artilliery has a big impact or little impact with very little in between.
And the more artillery UNITS you have, the better the chance you have of artillery making a big difference (more support units, the better) IF they are in supply, IF they have AMMO, IF thier experience level is decent and you have a decent leader for passing checks.
Now, the one other point is that you have three kinds of artillery. Long range guns that impact things at "long range" part of the battle (and fire at medium range), the medium range guns at the "medium range", and direct fire guns such as ATG at short range. And the medium and long range guns don't seem to fire at "short range". And its not quite that clean - some guns act as medium guns and then switch to act like ATG guns (the famous German 88 being one).
And to make things clear, this all comes from me playing around with the game system and doing test in the editor, making observations, recording them, and then making small changes and re-testing. So its all inferences about the combat system and observations not opening the code and reading it.