Of all the Japanese aircraft (thus far) in World of Warplanes, there is a very close tie between tier VI Kawasaki Ki-88 and tier VII Mitsubishi J4M Senden as my favorite planes.
Both aircraft share some of the same characteristics, like being armed with two smaller caliber machine guns and a big "bye bye" cannon. Although they are excellent climbers, both also suffer from weakly powered engines, the J4M Senden does get the edge with a longer boost duration going up, the Kawasaki Ki-88 feels better in a power dive.
I could come up with more comparisons and differences and there wouldn't really be any point to it. These are two totally different aircraft, they perform unique roles based on their strengths and weaknesses. One is a fighter, the other is designated as a Multirole.
However, the Senden does bring a flexibility factor to the battle that the Ki-88 seems to lack....