Option to choose the weapons of a IV race when building one. This way you may leave it default (current selection which isn't bad at all), or choose only certain weapons in order to be a bit more diverse.
For example only 9mm pistol for every shooter would suit more long IV races, return of the deagle might be acceptable for certain races where it'll be hard to aim, etc.
I think it'd make IV races more diverse, and it adds a way to judge new IV races (good weapons selection for the type of race or not).