trurle
Banned
First of all I doubt warlordism can be removed so quick-n-easy - Chiang was still unable to do it by the Second Sino-Japanese War and the incorporation of those warlords into the ROC made corruption even more rampant, reducing the efficiency and effectiveness of their war machine.
However, assuming it does take place: they'd lose it due to needing all troops fighting both the Communists and Japanese, and with the Soviets having all the intent of taking them back. Even if the PRC was propped up quickly enough they wouldn't be able to bargain for the lost territories.
IF they fight both Communists and Japanese. As i said earlier, the Japanese were opportunistic. The direction of their main strike was not decided up to March, 1941. If the Soviets are intensively fighting with Japanese..and if Japanese start fighting USSR earlier (1934-1937 instead of 1939) (before mass introduction of efficient Soviet BT-5 and BT-7 light tanks) and not losing to Soviets outright..the whole balance of power swings much more to the Chinese side.