Basicaly what this does is it forces the gunner to actualy run around, take a lap on the ship and place those ammo types that will put those guns in an advantage.
It does not buff gunners, as much as it takes away from engineers and pilots. Weapons like the mine launcher, artemis, flamer, hades and maybe some other are going to rely on a gunner being able to change the gun, while other classes are limited to work with one all around asumed standard ammo type for those guns that are prefered to be changed.
There are still weapons where people prefer only one ammo type. Like the hwacha with the heavy clip. Place an engineer with heavy clip on that hwacha with the new concept and you only do 15 rockets of explosive instead of the difference of 20. Engineers and pilots will still be useful to the guns if they choose correctly, but gunners will have a better purpose because of the limits that pilots and engineers now have.
This fixes a bit the role of a gunner, doesnt buff it. But makes it more so. Add in potentialy new ammo types or ammo type overhaul for the future, all of a sudden. Gunners dont seem that useless.
The goal is to place the gunner in a more valuable position.