Spent some time in the KI-84 last night. Its a wonderful airplane, and Beastly in some respects, yet I would not call it a Beast! Its is fully capable against any late war prop airplane, even a Beast! And thats whats so "Beastly" about it. The Hayate is capable of exploiting something against almost any adversary. Maybe if it was faster across a wide range of Alts, or had 4 20mms, it would be a Beast!
As it is its just Beastly good. A very well balanced airplane. Wasnt there a production version with more and/or bigger cannon?