Lore-wise shouldn't the Hissho get Legendary Warriors III? or something similar? I mean their history comes from being Gladiators. Their infantry should be top tier at least.

I think it would be a cool idea to have certain Factions excel in certain areas of ground combat. United Empire could have a little bit better tanks, Sophons could have great aircraft, Vodyani, Cravers, and Hissho have better infantry. I don't like that once you get access to tanks everyone goes all in 100% tanks for the next 30+ turns because no one will have access to aircraft for a while. Maybe this could mix things up a bit?