Its kinda a silly argument. Why can’t Germany have Osttruppen and Vichy France soldiers? I don’t think ppl want to see collaboration armies in the game (for very obvious historical reasons), but the weapons are fine.
I don’t think China as a proper sub-faction is necessary. China is great for event squads and weapon additions and can benefit both Allies and Soivet based on nationalist and communist affiliations. The problem of subfaction is that it may overtake the main faction because of recency bias and balance. The format of event squads is good enough.