As the title says. The British and German factions have plenty of characters you can choose to set up your company but at the current state the US and Japanese lack these options.
As an example if I would like to set up a male or female only squad for Japan I only have 3-3 models to choose from so two soldiers out of the 4 would use the same model.
It would be even okay just to add the German and British characters for the US and add one extra male and female model to the Japanese side. More options - more variety.