That’s what I guessed. Shields really are very good. And being able to add modifier to them would be over powered, making them too strong. Right now I even wonder about the higher tiered shields and how good they’d be compared to the ones there are now.
Helmets do seem a bit bland. I’m sure in the future they would have more stats like magical resistance and such, IF there will be magic classes.
And ammo was just a random thing, since in the skill tree it said adding modifiers to craftables. And ammo is a craftable. 😛