I was really thinking about this actually. In game, that would mean moving the generic "Ki-102" label to 1944 CAS and the Ki-83 being added to 1944 heavy fighter. It isn't TECHNICALLY correct, because not all Ki-102s were CAS, but it is clear that Paradox doesn't want sub-variants on the tree. Most people wouldn't even know not all Ki-102s were CAS, and plane nerds like us would just have the otsu in mind. I know they have the "G3M1" as the 1936 carrier-based attack aircraft

currently, but I think that is the result of them literally trying to do the impossible (finding only single-engine, land-based naval bombers) and discovering they don't have enough names for their carrier variants, because they already tied them to land-only.
As for replacing the Ki-32 with the Ki-48, I would be fine with it though, for the sake of possibility, I want to minimise the amount of new artwork required if the changes were made. Ki-32 is an acceptable choice for the 1936 slot. I really like the Ki-51 in the 1940 slot (beautiful plane that saw a lot of use). Both are already on the tree. My personal view is that I don't want to change what works, just what is objectively wrong. i.e. The travesty that is the current naval bomber line.