OKW and ost lack a lategame spamable allrounder tank.
Panther is good vs armor, but lack good AI, when you spam panthers, you stay there with 3 of them and try to kill one AT gun or ptras penals for ages.
you can spam p4 as okw..which lack HP and range and are eaten by anything lategame.
ost can build brumbars, which let you struggle vs any kind of lategame armor.
while all allies running around with their allrounder tanks Comets, T34-85 and Easy8. and demolish everything in their path, when be spammed.
There is just so much.....wrong with all of what you said.