Oscars get better over time and since they're Army you shouldn't have a shortage of good pilots if your training program is adequate to the task. They are actually about equivalent to the Zero which served the IJN well for much of the war. Like all Japanese fighters (early) they are undergunned. Because of their range and, beginning with the IIa, their bomb load, they will be quite useful well into the war. With the IIa, if you've trained them in naval attack as well as escort you have something that will be quite dangerous against enemy shipping and auxiliaries like mine layers and sweepers. I haven't tried it but I bet you could train them for ASW roles as well with success. What I want to stress is that the IJN will always be short of air crews and fighter pilots should only be trained for fighter missions and used sparingly at that. Because the Oscar is an IJA plane and because of the capabilities it inherently has, it is a very important aircraft indeed, if used to its potential.
As Japan, the last thing i want to do is fly "zero" equivalent fighters against 1944 allied airframes
To use the Oscar as a naval bomber is not sustainable into 1943.
Best use of Oscars is Kamikaze fodder in 1945.
Even if i train enough pilots for the losses, the training and airframe losses are still vauable production pieces, and pressure on the economy.
I rather go for a airframe that survives combat and gives my hard trained veterans a good chance.
What does Japan get for producing massive amounts of Oscars when they are shot down in droves? it cost fuel, resources, HI and a well trained pilot.
Tojos for me anytime, they cut down allied fighters and bombers in a way the oscar can only dream off, and when the airframe appears that can mingle, it is outdated with the new generation of fighters arriving.
COmplete waste of industry for Japan, use Oscars for the first few months, then switch to Tojos.