Why is Ki-84 perk?
Surely Ki-84 is the best IJAAF fighter.
But see below,
Those planes are not perk plane:
Bf109G10, Fw190D9, P-51D and N1K2.
Ki-84 can't out-turn from these planes, except N1K2.
And Ki-84 maybe can't out-turn N1K2, also Ki-84-I-Ko doesn't have 4 20mm cannons loadout.
I think that HTC won't release Ki-84-I-Otsu, 20mm*4 version of Hayate before releasing Ki-84-I-Ko.
So it shouldn't be perked.