I think if Kawasaki had realized the problems with the Ha-140 inline engine earlier, they could have jumped at a chance to find a replacement that involved the Mitsubishi Ha-112-II engine, which started to be available in quantity by circa late 1943. As we all know, the Kawasaki Ki-100 turned out to be one of the best Japanese fighters of World War II, with excellent maneuverability minus the mechanical problems that plagued the Ha-140 inline engine and Nakajima Ha-45 Homare radial engine.
In fact, I wonder why didn't Mitsubishi themselves design a true replacement for the A6M earlier that used the Ha-112-II engine. The IJN could have operational a true A6M successor by early 1944 that would have easily beat the F6F Hellcat and be even a serious threat to the F4U Corsair.
In fact, I wonder why didn't Mitsubishi themselves design a true replacement for the A6M earlier that used the Ha-112-II engine. The IJN could have operational a true A6M successor by early 1944 that would have easily beat the F6F Hellcat and be even a serious threat to the F4U Corsair.