Myself, I find the Ki-61 to be a much better fighter than the A6M5. The only thing the Zero does better is climb. Zero sucks at high speed, its slower, it dives poorly, and its armament is no better. The Ki-61 has few real flaws, except its slower than an F4U-1. In real life, serviceability was its main drawback, something not modelled in AH.
As for the F6F-3, air to air, it is no different (that you would notice), than an F6F-5. As for the Ki-61 we have in AH2 being slower than its 1943 counterpart, the difference might be a whopping 5-8 mph. I have seen no data that shows any appreciable speed difference in the Ki-61 models, 360-368mph is the big spread. Again, I would say the difference is negligable.
The Ki-45 would be a great addition as a bomber killer, and its a twin engined type, so that adds something to the IJ set.
Just my take on some of the comments.