assault is now merged with the medic class...
...
Assault is the most well-rounded class, odds are it will be the most commonly played. Giving them the medkit ensures that there will be plenty of healing to go around, almost eliminating the need for health regeneration.
Likewise, the support class is probably going to be reloading their machine guns quite often with bullets still in the magazine. Giving them the ammo kit lets them replenish the rounds they lost.