With the Pacific theatre coming up we must remember the Type 100 smg was extremely rare and highly sought after and only around 8,500 of all variants were made.
Japan only issued these to Commanding Officers and they were known for being extremely controllable but lacked power despite being a bottlenecked cartridge that Could handle much higher pressure.
Make it special by only allowing the Squad Leader to use it and make it have extremely low recoil.
Type 100/44 has solid wood stock and muzzle break 7,500 made.
And many of those guns were sunk on there way to battle due to the US Navy and Air Force so that significantly decreased the amount of type 100s that made it to combat.
Gold ticket weapons are already limited and most premium squad weapons were produced in 2 to 3 digits and since premium squads cost money people rarely use them
So with this logic; tanks also have to be limited spawns for japanese. Very few tanks were used in pacific and japanese total tank production was lower than 10 k .
In this situation you have to give huge defensive advantage to japanese like monster pillboxes and labyrent like tunnels, carved out and well protected mg spots in reverse slopes of hills and mountains.
This is what they actually did. They were not stupid and very well aware of their fire power weakness. After they lost their naval forces in midway and philipines sea, japanese tried to readress their handicap by defensive war. If devs limit or removes smgs, tank planes etc… war will turn into blowtorch and corcscrew job. Americans pouring flames and throwing tnt to every hole they see while japanese try to snipe americans from diatance with rifles and mgs