I've often wondered the same. The Ki-84-Ia is basically THE ideal field defense plane.
- The plane has the one of the shortest take off distance required among all planes
- Can start maneuvering right after its wheels are retracted, thanks to the massively efficient flaps
- Has very fast rate of acceleration and great climb
- Not great, but still has 300 rounds of cannon with 150rpg each wing
- Much faster than the Spit5 or Spit9 at deck
- Has great fuel load and range, so it could fly for a very long time even at 50% fuel
- Outturns everything that turns worse than a N1K2
- Good maneuverability and stability at all speed ranges except over 400mph
- Superior in the vertical, the only plane which can hang long enough to match a P-38
- Superior in flap efficiency, also the only plane which can play the P-38 at its own game and still win
The only reason I can think of why people don't fly it more often, is that they've expected so much of a superplane out of it that the initial disappointment still discourages people from choosing it.
They have the wrong opinion that the Ki-84 is a castrated plane, which it is not. Having read the many posts and discussions about the Ki-84 when it was released, at least my personal conclusion is that the Ki-84 in AH2 is modelled reasonably.
