Is there any faction, in your conception, or game, that is not bad designed?
Wehr.
You have diverse tiers which encourage combined arms.
You have multiple stock infantry and armor upgrades, allowing for what is mostly missing in coh2-decision making and actual resource management(to a point USF also got that).
You are encouraged, but not forced to pick specific doctrines.
You have good infantry and armor scaling.
Most units and off-maps have a role and are usable(aka no completely useless ones, maybe except encirclement doc one).
You have linear power progression, you are not punished for picking wrong tier.
You have EXCELLENT resource management possibilities through luftwaffe supply, luftwaffe support, Mechanized support and osttruppen doctrines.
The single problem they have is the T3 to T4 transition cost and maybe T1 to T2 as well.
3 remaining armies have pretty huge design flaws related to tier structure, munition management and teching choices.