I would personally be much more interested in the Ki-61-II than the Ki-100, though historical relevance makes it unlikely the Ki-61-II will be added. As Butcher says, the Tiger II was also extremely unreliable and it is in. That said, the Tiger II also has an awe factor about it that the Ki-61-II decidedly lacks.
Probably the only Japanese unit that has it is the Yamato. Long Lance is good too.
Japanese tanks are not something to be "Wow'ed" over either, I did a pictorial history on the Japanese Army Armour a few years back, to my surprise not one tank was capable of taking on an M4 Sherman on equal grounds.
Well except one prototype:
The Type 5 Japanese tank was suppose to have a 75mm main gun and 37mm aux gun, it was the "Panther" of the Japanese armour in 1945, they believed it would be superior to M4A1 Sherman. Only one prototype was completed, it was actually "taken" from the Japanese island because the 37mm was installed, if it wasn't installed it would of been left to the Japanese Defense force.
(Sorry for going off topic) - but its just an example of just how "bad" some things were for the Japanese Army, they were trying to design a Sherman killer in 1945.
Back to the Ki-61, I had fond memories of flying it in Scenarios and FSO's, even scored 9 kills in an FSO event (Rangoon of all places) - mostly because I was flying against Brewster Buffalos and P-40B's. In a typical FSO setting with F4u-1's, P-38Gs and P-47-D11s the Speed and lack of maneuverability above 16,000 ft start to show. I only got lucky once when I ran into a gaggle of F4F's and was boom and zooming them without a problem, however the first corsair I ran into; I ended up flamed.
Overall its a solid aircraft and performer, it just has mediocre maneuverability, speed and climb rate - just nothing that jumps out at you vs an Ki-84. I honestly would like to see other Japanese planes added, Ki-44 for example or Ki-45.