As I mentioned before, I think a little modifier version of RT Universal talent would make sense.
> Simple Weapon Training: SP, Laser & Low-Tech Melee Weapons / Throwing Weapons
> Advanced Weapon Training : Chain Weapons, Shock Weapons, Flamer, Low-Tech Ranged Weapons (as they are rarer in use), Grenades, Chain Throwing Weapons, Bolt Weapons, Force Weapons, Launcher Weapons
> Professional Weapon Training: Plasma Weapons, Power Weapons, Melta Weapons, Power Throwing Weapons
> Heavy Weapon Training : is needed for the Heavy versions of above categories
> Exotic Weapon Training (as now)
It would allow for different proficiency level and still be compact enough.