That Japan move leaves some nice openings for the Allies (remember I said a UOSA IC was viable in a SJF game).
Russia will have 6 INF massed in Bury after R1 (typical SJF R1 move). W/o major reinforcement of Asia, Manchuria falls on R2 (+3 to Russia).
Sinkiang will also remain US Controlled, inviting another IC by the Allies on US1 due to the lack of Japan forces in Asia
2 INF, 1 ART, 1 ARM are dropped from EUS into Algeria on US1, and a ship or 2 to reinforce the SZ55 fleet.
Now, is Japan going to go full tilt toward Africa under those circumstances? Probably not the best move Japan can make at that point.
Again, I am not saying a UOSA IC is an excellent strat, but it is a viable strat, especially if not countered correctly. And your statements above are not the best counter because:
1. It draws Japan away from their main economic expansion areas early and allows Russia to gain income (and more men to counter Germany).
2. It forces Germany to keep sending forces to the African meat grinder ($6 minimum per turn)
3. It allows the US to Island Hop, unless Japan spend more money on fleet (more IPC’s not going into manpower against Russia)
And ARM built in UOSA is not completely wasted even if Africa is abandoned by the Axis. 3 turns to get ARM to Caucuses to help the Russians, compared to 2 turns from London via TRNs in SZ4. Not that much of a delay in exchange for keeping Germany down $2 instead of up $10 in Africa.