Shuckins,
The Ki.43 Hayabusa "Oscar" was the second most produced Japanese fighter. You are correct about that. 5,919 Ki.43s were built.
However, the late war Ki.84 was the third most produced Japanese fighter and had the highest one year production total of any Japanese aircraft ever. 3,514 Ki.84s were built.
The Ki.27 "Nate" was produced in large numbers (unlike the Navy eqivilent A5M "Claude"), but like the A5M the Ki.27 played no real role in WWII. This is especially true as only the P-40B is available as a historical opponent in AH. 3,399 Ki.27s were built.
So, as you can see, you're blanket statement about late war Japanese fighters is not true.
I do think that a Ki.43-II is a required aircraft for AH as some point, but as the Japanese have been getting the turkeys for awhile I think the Ki.84 would be a better addition at this time.