My suggestions of OKW fix:
Make obers LMG cost munitions
Buff raketen
Nerf schreck long range accuracy
Nerf volks incoming accuracy veterancy
Decrease fuel cost of jagdpanzer
This will:
Make munitions precious making you not want to spam schrecks. And reducing the risk of a huge blob with botch epic AI (obers) and epic AT (volks).
Make volks a little bit more squishy.
Give you a reliable early game counter to light vehicles (raketen).
Give you a good medium tank counter in mid game (jagdpanzer).
This will not fix anything. as some people already said the shrek is a crutch. the okw really doesnt have good AT guns and you are forced to buy shreks.