The day okw will start with tier 0 grenatenwerfer/flame car/flamethrower they will lose flame grenade
The day okw will start with tier 0 AT gun, they will lose the panzerfaust. Oh wait...
Seriously, though:
1. Give volks mp40 upgrade instead of stg.
2. Move their nades and pfausts to separate T0 upgrades soviet style, no other restrictions.
3. Swap searchlight and obers in tech.
That way okw can either go for buffing their base infantry with upgrades or rushing one of two powerful units - obers and luchs. This gives 3 interesting build paths. If okw needs to supplement their choice they can always build AT and basic infantry at base, go for upgrade or side tech. If they need firepower at range - they build LeIG or obers. If they need firepower up close, they upgrade volks, if they want to pick up weapons and team weapons they don't upgrade but go for them with base volks.
IMO that makes it as easy to understand and fun as either soviets or ostheer design.
One could say that obers that early are too early but I don't think that will be the case. They will not be supplemented by huge volkblob buffed with all the abilities and by luchs or other armour so there is always a possibility to counter with light vehicle play. And having more than one viable build path is worth the risk.
Do mind that there might be some small fuel cost increase to med truck needed in order to avoid obers coming too early. Or increased muni cost for their mg upgrade so that they have to fight with kars only if you make too many of them.