New feature: troop carriers should resupply infantry ammo and revive +20% soldiers.
Now you can get autistic about it and pretend they have extra supplies inside, medical equipment, or they have only give ammo corresponding to AA, AT they themselves carry out of their own pool.
But by any method it would give them a bigger role. It would also make up for infantry being so slow that a standard resupply takes longer than just having them die off and replaced with a chopper drop.