My "Japanese wishlist":
B6N2 - carrier torpedo bomber/level bomber, replacement for the B5N2
B7A2 - carrier torpedo bomber/level bomber, replacement for the B6N2, all carriers lost before it entered service
D4Y1 - carrier dive bomber, replacement for the D3A, fastest dive bomber of WWII
H8K2 - well protected high performance flying boat, patrol aircraft/bomber/torpedo bomber
J2M3 and J2M5 - interceptor with good climb and decent speed
Ki-43-I, Ki-43-II and Ki-43-III - most common IJA fighter, lightly armed and built but extremely maneuverable
Ki-44-II - Moderately armed interceptor with good climb and decent speed
Ki-45 - twin engined fighter of modest capability
Ki-61-I-Ko - early version of the Ki-61 with four 12.7mm guns and better turning ability
Ki-61-II - late version of the Ki-61, faster, more ammo, cut down rear fuselage
Ki-84-I-Otsu - Ki-84 with four 20mm cannons and perhaps a slightly more powerful engine, might be a light perk plane
Ki-100 - Ki-61-II airframe with a radial engine, slower, better climb
Ki-102 - twin engined attack aircraft with decent performance and some larger guns
N1K1 - float plane fighter
N1K1-J - land based interceptor based on the float plane fighter, a bit lower performance and much less ammo than the N1K2-J
P1Y1 - bomber/torpedo bomber with good performance and the ability to carry two 500kg bombs which would make it very useful for a Japanese bomber
I fly the K-84 quite a lot, and wouldn't mind trying a 4 cannon variant myself. The Ki-100 I am always a +1 on, and the J2M would be nice as well.
I have always wanted an a better Japanese attack plane - The D4Y1 would be a nice addition as well +1.
After that, they can bring me the B6N - but I'd hope they do something about the balancing the torpedo system first (otherwise it would be a waste).
Early war Ki-27, 43, 44 would be wonderful for scenarios, but I don't think they would get much MA time.
P1Y1 would seem to fit the same role as the Ki-67, and I would only be in favor of floatplanes if they were enabled at ports.