I agree with Scharnhorst. I'd love to see this as a new slot if that is doable.
Its doable but I don't see the point.
The stock CVGeneric is pointless.
All it does is duplicate another ship.
For that matter all of the other so called Generic ships are pretty pointless as well.
Sure there is a point ... there were many more Japanese CV's than the 6 used at Pearl Harbor.
For example, the Junyo / Hiyo CV's, or the Unyo / Taiyo / Chuyo CVE's.
And this does not even get into the various CVL's Japan had.
So to answer your question about what the point is, the point is to be able to use some of the lesser known but equally important CV's of the Japanese Navy instead of being restricted to the same old 6 CV's used in every wargame since the beginning of time. This can add a little more flavor.
But alas, it is just a request. I am privately looking into modding files myself on my own time. I am no where near being able to do this yet ... but in time perhaps. Otherwise I would do it myself, but I am trying to learn the basics as we speak.