Reinforce and Pop cap affect Float DRASTICALLY. And your underestimating power of units and force concentration. When 1 unit costs double of another and does double the DPS of the other it is exponentially superior due to force concentration and availability of cover.
Example if I am used and have a 50 Pop cap with vehicles and infantry I am bleeding 100 MP a min.
OKW with the same relative power but 75MP a min drain due to no vehicles and just infantry carrying all sorts of counters like Shreks and High AI DPS can easily run into the opposing force and instantly start inflicing casulties in a smaller area and instantly retreat before they take any themselves if they sense it wont be a steam roll.
Having super high DPS infantry you can Alpha strike and retreat for no loss to your own MP but a loss to the opponents.
AI/AT power to unit effciency is NON LINEAR. But its currently treated in a Linear fashion.
A OKW player with no armor will get his ass kicked just like any other player that forgoes making any kind of armor, but more than often as OKW you are not getting any kind of choice.
You can't make tanks because the game won't let you. It gates all your vehicles behind large costs on top of a fuel penalty meaning that you normally will only ever be seeing 10% of OKW's unit roster in a game because there is little incentive to diversify your army thanks to the resource disadvantage.
Your looking to hard a OKW in a vacuum. OKW's infantry really isn't anything to call home about when things like Shocks, 1919 Para's and Riflemen, as well as the finally viable guards exist. Every faction has a plethora of good infantry now, but with OKW infantry is all they have.
Instead of thinking about how you can adjust OKW in a vacuum, think about why the other faction's don't float MP. It's because they all have MP dumps, tanks, and more than 2 fucking support weapons.