I was really referring to the attitude of "Why do we need the Ki-43-III when the Ki-43-I or -II can just be subbed for it?" while slight differences between the Bf109E-4 and Bf109E-7, as an example, are seen by sometimes the same people as a "must have, needed to fill a gap, addition."
I think its because that when people think of the japanese airforce, they think of the zero, the kate, and the val. Most don't go "Japanese airforce....... oh yeah, they flew the Ki-43, the one with 2 12.7mm mg's!". When they HAVE heard of the hayabusa, they have this image of a fighter tickling a wildcat with its 7.7's only to be turned into a flamming wreck when another wildcat shoots at it.
It also has to do with use. People want what they themselves will use. I for one don't fly the A6M3 except on rare occations and I can say I very apathetic to its addition. On the other hand, I would be thrilled to get a 109E-7, or an F-6 dispite their admitedly modest improvments over the previous version, mostly because I would actually USE them.
