I think if you have it, then you might as well use its full capacity. They will be expensive ships though. I read somewhere that the radars by themselves are worth $3B a set. Will make a Hunter look cheap in comparison.Was it not possible to modify Japan's land Spy7 panels for ASEV, i.e. smaller or was it less expensive to just build a larger ship?
I suspect if they had a clean slate and didn't have spare radars, Japan might simply have evolved the Maya class with a spy6 radar and Aegis baseline 10 package, similar to a flight III AB.