IFVs for top tier minor nations

Japan has these options for 10.0+ Br The CCV can be used as a IFV/SPAAG. Would prefer it as a SPAAG though. It will be far more stronger than the Soviet 2S38 and German Puma. Probably better than the Otomatic if not identical.

B78 IFV works for the 8.3 or 8.7Br

i have a question that why japanese dont like to improve there vehicles but design a new one, just like Type90, it only has a B improved version, but even has not big different with Type90, then they designed the Type10