I am not arguing that. The scale of a tank unit certainly is bigger than everything the chinese nationalists fielded in real life as a unit. However the same is true for the romanian tank unit - consequently it would also have to be removed.
Now as far as I'm aware the unit doesn't even represent a single tank corps (propably about 120 - 200 tanks for Soviets, 200 - 300 for germans) but a tank group of serval tank corps. I'd guess that would be around 300 - 600 tanks. (The 200th Div. had around 100 tanks according to the source you quoted from)
Also from the same 'wiki' article you quoted:
Soon relations were made with the USA who only slowly began to (officially) provide help and 233 U.S. M24 light tanks were acquired by the Nationalists when America entered the war along with some 48 M3A3, M5A1 Stuart tanks in Lend/Lease from the USA in 1943, and 35 M4 Sherman tanks were acquired under the United States Military Assistance Program between 1943 and 1944.
So the amount of tanks delivered by the US alone would be around 300. That's why I consider it not 'impossible' to form such a unit... these tanks were certainly spread thin in real life, but the possibility to send more and concentrate them would have existed. Feel free to correct me in this matter though.... Also in game terms: China can't afford to do research for the tanks so the effect of the unit is not that big...it will stay a 'light' tank group forever. But I'm afraid we propably won't totally agree on this matter. Even though even I think there should be a clear decision event to finance this unit through the US.