Trust me on this one, Mut: the Frank is a great plane. She about the only ship in the game I'm concerned about encountering in a Hog.
Meh, that's only because you hog drivers love to drop flaps to out-turn aircraft you can also run down. Although it is a little slower at low altitude, the Ki-84's butterfly flaps blunt this wunder-tactic completely.
On the other hand, if you're flying the F4U as more of an energy fighter, i.e. fast, the Spit XVI is a far greater threat than the Ki-84 because it doesn't lose elevator control at 300mph+, and unless you really yank the stick, it's not going to lose parts.