We did the best we could (oil excepted) to limit the growth of the Japanese economy to historical proportions. I am sorry it was not good enough for you, but Don and Joe did their best.
In my mod the jets are removed as they were not developed in Japanese r&d facilities, but developed from German data. Other aircraft, such as the Ki44, could have been built in great numbers, like the Ki43 and A6M were, that was a real choice the Japanese made that we felt the player should have.
Economy growth is limited at the starting end by resources; there are more resources in the game than Japan used during WW2 but not much more, and a limiter is getting the resources to Japan for production. I have seen AARs where the allied player did not put much work into sinking merchants and the Japanese had a great economy, and games where the Japanese were unable to get their resources home and their economy tanked at the beginning of '45.
If you pay attention to games and tests, we found that the Japanese economy actually tends to implode several months earlier than historical, but I think that is players over producing and that is exactly what we went for.
So, no, Don & I did not feel that the Japanese favoritism that you allude to is very strong. I would maybe argue that Allied favoritism is just as strong, but you don't see what you do not want to.