Early game:
Maxim Spam
US AA truck
USA BAR blob
M3/Penal/Guards
Lack of OKW AT options/effectiveness
OH grens sucking bad vs Rifleman with severe lack of options vs USA
Mid to late
Lack of OKW AT options/effectiveness
T-34 85 call in - OP
Panther sucking bad and being ridiculously expensive
IS2 - post buff
ISU152
I can see that being an issue.
I play mostly 2v2 and above, so I often can avoid these issues. 1v1 these issues seem to be less easily countered. However I do believe all of these issues do have counters by all factions regardless whether the production of the counters are truly price effective.
Propagandacast do have a lot of vids that do prove OKW can win games. I will list the conters I know against the early game tactics of allies:
IG artillery and Ostheer Mortar : For both Maxim and Us blobs.
Ostheer Sniper: Zero counters for US early game.
Unbreakable wires: Effective entry denial that requires medium vehicles to crush. Effective against early M3 and US blob flank.
Assault Grens : Great pick against US rifle spam early game.
I got nothing for lack of AT though.