The general is right. Japs have weaker units than the other major contries in the game. The army you choose look preaty good. But you shouldn’t always use the same army if you play with the same persons because they will adapt very fast. If your opponent get a IS-2 you’ll have to be lucky to take it out. But the good news is that this unit is so expensive that you rarely see one in 100 pts games.
I trick from my brother si to use a mortar with your SNLF captain. Infantry will need 6 on their cover roll to survive and you can shoot them safely from 8 hexs !! This is very good to get rid of the enemy infantry even when the have some cover.
Use your paratrooper to get rid of dug up MGs. Most of the time they will get killed in the process but if you get rid of the MGs, you infantry (most part of your army) will breath easier.
As I said earlier you must not always choose the same units or your opponent will choose according to this selection. I would recommend using one or more 47mm Type 1 anti-tank gun. They are cheaper than tanks and are less vulnerable to tank attack.