That you think the A6M is more similar to the Ki-43 than the Bf109E-4 is to the Bf109E-7 is funny.
The Bf109E-7 is a Bf109E-4 with a very slightly more powerful engine and drop tank capability. Bf109 fans whining about the lack of the Bf109E-7 is like Spitfire fans whining about the lack of the Spitfire Mk II.
I think you are much more familiar with the German equipment and so the difference in each model mean a lot to you as you see their significance. Your weakness is that you downplay and dismiss the differences between things you are not as familiar with.
On the one hand you are right, the A6M and Ki-43 both pretty much have to play the turning game against the American fighters. On the other hand, you are wrong in that one can dismiss the differences between the Bf109 and Fw190 by saying one can sub for the other as against Spitfires and Hurricanes both have to avoid turn fights.
The fact is that the Ki-43, fragile and inadequate as it was, was one of the core fighters of WWII, right up there with the Bf109, Fw190, Hurricane, Spitfire, LaGG/La series, Yak series, P-38, P-47, P-51, F4F, F4U, F6F and A6M.